fix "set_real_ip_from unix:" inheritance

src/http/modules/ngx_http_realip_module.c

diff --git a/src/http/modules/ngx_http_realip_module.c b/src/http/modules/ngx_http_realip_module.c
index 7942042..b88b122 100644
--- a/src/http/modules/ngx_http_realip_module.c
+++ b/src/http/modules/ngx_http_realip_module.c
@@ -26,7 +26,7 @@
     ngx_uint_t         hash;
     ngx_str_t          header;
 #if (NGX_HAVE_UNIX_DOMAIN)
-    ngx_uint_t         unixsock; /* unsigned  unixsock:1; */
+    ngx_uint_t         unixsock; /* unsigned  unixsock:2; */
 #endif
 } ngx_http_realip_loc_conf_t;
 
@@ -411,10 +411,12 @@
      *     conf->from = NULL;
      *     conf->hash = 0;
      *     conf->header = { 0, NULL };
-     *     conf->unixsock = 0;
      */
 
     conf->type = NGX_CONF_UNSET_UINT;
+#if (NGX_HAVE_UNIX_DOMAIN)
+    conf->unixsock = 2;
+#endif
 
     return conf;
 }
@@ -428,11 +430,14 @@
 
     if (conf->from == NULL) {
         conf->from = prev->from;
-#if (NGX_HAVE_UNIX_DOMAIN)
-        conf->unixsock = prev->unixsock;
-#endif
     }
 
+#if (NGX_HAVE_UNIX_DOMAIN)
+    if (conf->unixsock == 2) {
+        conf->unixsock = (prev->unixsock == 2) ? 0 : prev->unixsock;
+    }
+#endif
+
     ngx_conf_merge_uint_value(conf->type, prev->type, NGX_HTTP_REALIP_XREALIP);
 
     if (conf->header.len == 0) {