rpm: dropped support for sysvinit.

The last OS that used sysvinit targets was RHEL 6, EOLed on 2020-11-30.
diff --git a/rpm/SOURCES/nginx-debug.sysconf b/rpm/SOURCES/nginx-debug.sysconf
deleted file mode 100644
index f79b453..0000000
--- a/rpm/SOURCES/nginx-debug.sysconf
+++ /dev/null
@@ -1,5 +0,0 @@
-# Configuration file for the nginx-debug service.
-
-NGINX=/usr/sbin/nginx-debug
-CONFFILE=/etc/nginx/nginx.conf
-LOCKFILE=/var/lock/subsys/nginx-debug
diff --git a/rpm/SOURCES/nginx.init.in b/rpm/SOURCES/nginx.init.in
deleted file mode 100755
index 4370c67..0000000
--- a/rpm/SOURCES/nginx.init.in
+++ /dev/null
@@ -1,169 +0,0 @@
-#!/bin/sh
-#
-# nginx        Startup script for nginx
-#
-# chkconfig: - 85 15
-# processname: %PROVIDES%
-# config: /etc/nginx/nginx.conf
-# config: /etc/sysconfig/%PROVIDES%
-# pidfile: /var/run/nginx.pid
-# description: nginx is an HTTP and reverse proxy server
-#
-### BEGIN INIT INFO
-# Provides: %PROVIDES%
-# Required-Start: $local_fs $remote_fs $network
-# Required-Stop: $local_fs $remote_fs $network
-# Default-Start: %DEFAULTSTART%
-# Default-Stop: %DEFAULTSTOP%
-# Short-Description: start and stop nginx
-### END INIT INFO
-
-# Source function library.
-. /etc/rc.d/init.d/functions
-
-if [ -L $0 ]; then
-    initscript=`/bin/readlink -f $0`
-else
-    initscript=$0
-fi
-
-sysconfig=`/bin/basename $initscript`
-
-if [ -f /etc/sysconfig/$sysconfig ]; then
-    . /etc/sysconfig/$sysconfig
-fi
-
-nginx=${NGINX:-/usr/sbin/%PROVIDES%}
-prog=`/bin/basename $nginx`
-conffile=${CONFFILE:-/etc/nginx/nginx.conf}
-lockfile=${LOCKFILE:-/var/lock/subsys/%PROVIDES%}
-pidfile=${PIDFILE:-/var/run/nginx.pid}
-SLEEPSEC=${SLEEPSEC:-1}
-UPGRADEWAITLOOPS=${UPGRADEWAITLOOPS:-5}
-CHECKSLEEP=${CHECKSLEEP:-3}
-RETVAL=0
-
-start() {
-    echo -n $"Starting $prog: "
-
-    daemon --pidfile=${pidfile} ${nginx} -c ${conffile}
-    RETVAL=$?
-    echo
-    [ $RETVAL = 0 ] && touch ${lockfile}
-    return $RETVAL
-}
-
-stop() {
-    echo -n $"Stopping $prog: "
-    killproc -p ${pidfile} ${prog}
-    RETVAL=$?
-    echo
-    [ $RETVAL = 0 ] && rm -f ${lockfile} ${pidfile}
-}
-
-reload() {
-    echo -n $"Reloading $prog: "
-    killproc -p ${pidfile} ${prog} -HUP
-    RETVAL=$?
-    echo
-}
-
-upgrade() {
-    oldbinpidfile=${pidfile}.oldbin
-
-    configtest -q || return
-    echo -n $"Starting new master $prog: "
-    killproc -p ${pidfile} ${prog} -USR2
-    echo
-
-    for i in `/usr/bin/seq $UPGRADEWAITLOOPS`; do
-        /bin/sleep $SLEEPSEC
-        if [ -f ${oldbinpidfile} -a -f ${pidfile} ]; then
-            echo -n $"Graceful shutdown of old $prog: "
-            killproc -p ${oldbinpidfile} ${prog} -QUIT
-            RETVAL=$?
-            echo
-            return
-        fi
-    done
-
-    echo $"Upgrade failed!"
-    RETVAL=1
-}
-
-configtest() {
-    if [ "$#" -ne 0 ] ; then
-        case "$1" in
-            -q)
-                FLAG=$1
-                ;;
-            *)
-                ;;
-        esac
-        shift
-    fi
-    ${nginx} -t -c ${conffile} $FLAG
-    RETVAL=$?
-    return $RETVAL
-}
-
-rh_status() {
-    status -p ${pidfile} -b ${nginx} ${nginx}
-}
-
-check_reload() {
-    templog=`/bin/mktemp --tmpdir nginx-check-reload-XXXXXX.log`
-    trap '/bin/rm -f $templog' 0
-    /usr/bin/tail --pid=$$ -n 0 --follow=name /var/log/nginx/error.log > $templog &
-    /bin/sleep 1
-    /bin/echo -n $"Sending reload signal to $prog: "
-    killproc -p ${pidfile} ${prog} -HUP
-    /bin/echo
-    /bin/sleep $CHECKSLEEP
-    /bin/grep -E "\[emerg\]|\[alert\]" $templog
-}
-
-# See how we were called.
-case "$1" in
-    start)
-        rh_status >/dev/null 2>&1 && exit 0
-        start
-        ;;
-    stop)
-        stop
-        ;;
-    status)
-        rh_status
-        RETVAL=$?
-        ;;
-    restart)
-        configtest -q || exit $RETVAL
-        stop
-        start
-        ;;
-    upgrade)
-        rh_status >/dev/null 2>&1 || exit 0
-        upgrade
-        ;;
-    condrestart|try-restart)
-        if rh_status >/dev/null 2>&1; then
-            stop
-            start
-        fi
-        ;;
-    force-reload|reload)
-        reload
-        ;;
-    configtest)
-        configtest
-        ;;
-    check-reload)
-        check_reload
-        RETVAL=0
-        ;;
-    *)
-        echo $"Usage: $prog {start|stop|restart|condrestart|try-restart|force-reload|upgrade|reload|status|help|configtest|check-reload}"
-        RETVAL=2
-esac
-
-exit $RETVAL
diff --git a/rpm/SOURCES/nginx.sysconf b/rpm/SOURCES/nginx.sysconf
deleted file mode 100644
index 6c31a48..0000000
--- a/rpm/SOURCES/nginx.sysconf
+++ /dev/null
@@ -1,4 +0,0 @@
-# Configuration file for the nginx service.
-
-NGINX=/usr/sbin/nginx
-CONFFILE=/etc/nginx/nginx.conf
diff --git a/rpm/SPECS/nginx.spec.in b/rpm/SPECS/nginx.spec.in
index 8791c57..415eabb 100644
--- a/rpm/SPECS/nginx.spec.in
+++ b/rpm/SPECS/nginx.spec.in
@@ -4,28 +4,15 @@
 %define nginx_group nginx
 %define nginx_loggroup adm
 
-# distribution specific definitions
-%define use_systemd (0%{?rhel} >= 7 || 0%{?fedora} >= 19 || 0%{?suse_version} >= 1315 || 0%{?amzn} >= 2)
-
-%if %{use_systemd}
 BuildRequires: systemd
 Requires(post): systemd
 Requires(preun): systemd
 Requires(postun): systemd
-%endif
 
 %if 0%{?rhel}
 %define _group System Environment/Daemons
 %endif
 
-%if 0%{?rhel} == 6
-Requires(pre): shadow-utils
-Requires: initscripts >= 8.36
-Requires(post): chkconfig
-Requires: openssl >= 1.0.1
-BuildRequires: openssl-devel >= 1.0.1
-%endif
-
 %if 0%{?rhel} == 7
 %define epoch 1
 Epoch: %{epoch}
@@ -81,11 +68,8 @@
 
 Source0: https://nginx.org/download/%{name}-%{version}.tar.gz
 Source1: logrotate
-Source2: nginx.init.in
-Source3: nginx.sysconf
 Source4: nginx.conf
 Source5: nginx.default.conf
-Source7: nginx-debug.sysconf
 Source8: nginx.service
 Source9: nginx.upgrade.sh
 Source10: nginx.suse.logrotate
@@ -114,11 +98,6 @@
 
 %prep
 %autosetup -p1
-cp %{SOURCE2} .
-sed -e 's|%%DEFAULTSTART%%|2 3 4 5|g' -e 's|%%DEFAULTSTOP%%|0 1 6|g' \
-    -e 's|%%PROVIDES%%|nginx|g' < %{SOURCE2} > nginx.init
-sed -e 's|%%DEFAULTSTART%%||g' -e 's|%%DEFAULTSTOP%%|0 1 2 3 4 5 6|g' \
-    -e 's|%%PROVIDES%%|nginx-debug|g' < %{SOURCE2} > nginx-debug.init
 
 %build
 ./configure %{BASE_CONFIGURE_ARGS} \
@@ -162,17 +141,9 @@
 %{__install} -m 644 -p %{SOURCE5} \
     $RPM_BUILD_ROOT%{_sysconfdir}/nginx/conf.d/default.conf
 
-%{__mkdir} -p $RPM_BUILD_ROOT%{_sysconfdir}/sysconfig
-%{__install} -m 644 -p %{SOURCE3} \
-    $RPM_BUILD_ROOT%{_sysconfdir}/sysconfig/nginx
-%{__install} -m 644 -p %{SOURCE7} \
-    $RPM_BUILD_ROOT%{_sysconfdir}/sysconfig/nginx-debug
-
 %{__install} -p -D -m 0644 %{bdir}/objs/nginx.8 \
     $RPM_BUILD_ROOT%{_mandir}/man8/nginx.8
 
-%if %{use_systemd}
-# install systemd-specific files
 %{__mkdir} -p $RPM_BUILD_ROOT%{_unitdir}
 %{__install} -m644 %SOURCE8 \
     $RPM_BUILD_ROOT%{_unitdir}/nginx.service
@@ -183,12 +154,6 @@
     $RPM_BUILD_ROOT%{_libexecdir}/initscripts/legacy-actions/nginx/upgrade
 %{__install} -m755 %SOURCE13 \
     $RPM_BUILD_ROOT%{_libexecdir}/initscripts/legacy-actions/nginx/check-reload
-%else
-# install SYSV init stuff
-%{__mkdir} -p $RPM_BUILD_ROOT%{_initrddir}
-%{__install} -m755 nginx.init $RPM_BUILD_ROOT%{_initrddir}/nginx
-%{__install} -m755 nginx-debug.init $RPM_BUILD_ROOT%{_initrddir}/nginx-debug
-%endif
 
 # install log rotation stuff
 %{__mkdir} -p $RPM_BUILD_ROOT%{_sysconfdir}/logrotate.d
@@ -236,17 +201,10 @@
 %config(noreplace) %{_sysconfdir}/nginx/win-utf
 
 %config(noreplace) %{_sysconfdir}/logrotate.d/nginx
-%config(noreplace) %{_sysconfdir}/sysconfig/nginx
-%config(noreplace) %{_sysconfdir}/sysconfig/nginx-debug
-%if %{use_systemd}
 %{_unitdir}/nginx.service
 %{_unitdir}/nginx-debug.service
 %dir %{_libexecdir}/initscripts/legacy-actions/nginx
 %{_libexecdir}/initscripts/legacy-actions/nginx/*
-%else
-%{_initrddir}/nginx
-%{_initrddir}/nginx-debug
-%endif
 
 %attr(0755,root,root) %dir %{_libdir}/nginx
 %attr(0755,root,root) %dir %{_libdir}/nginx/modules
@@ -272,13 +230,8 @@
 %post
 # Register the nginx service
 if [ $1 -eq 1 ]; then
-%if %{use_systemd}
     /usr/bin/systemctl preset nginx.service >/dev/null 2>&1 ||:
     /usr/bin/systemctl preset nginx-debug.service >/dev/null 2>&1 ||:
-%else
-    /sbin/chkconfig --add nginx
-    /sbin/chkconfig --add nginx-debug
-%endif
     # print site info
     cat <<BANNER
 ----------------------------------------------------------------------
@@ -317,20 +270,12 @@
 
 %preun
 if [ $1 -eq 0 ]; then
-%if %use_systemd
     /usr/bin/systemctl --no-reload disable nginx.service >/dev/null 2>&1 ||:
     /usr/bin/systemctl stop nginx.service >/dev/null 2>&1 ||:
-%else
-    /sbin/service nginx stop > /dev/null 2>&1
-    /sbin/chkconfig --del nginx
-    /sbin/chkconfig --del nginx-debug
-%endif
 fi
 
 %postun
-%if %use_systemd
 /usr/bin/systemctl daemon-reload >/dev/null 2>&1 ||:
-%endif
 if [ $1 -ge 1 ]; then
     /sbin/service nginx status  >/dev/null 2>&1 || exit 0
     /sbin/service nginx upgrade >/dev/null 2>&1 || echo \