debian: added explicit Conflicts with nginx-common.
diff --git a/debian/nginx.control.in b/debian/nginx.control.in
index d9fbf27..ae17f06 100644
--- a/debian/nginx.control.in
+++ b/debian/nginx.control.in
@@ -17,6 +17,7 @@
 Architecture: any
 Depends: ${misc:Depends}, ${shlibs:Depends}, lsb-base (>= 3.0-6), adduser
 Provides: httpd
+Conflicts: nginx-common
 Description: high performance web server
  nginx [engine x] is an HTTP and reverse proxy server, as well as
  a mail proxy server.