Fixed PROXY protocol on IPv6 sockets (ticket #858).

src/http/ngx_http.c

diff --git a/src/http/ngx_http.c b/src/http/ngx_http.c
index d09e3f0..64af447 100644
--- a/src/http/ngx_http.c
+++ b/src/http/ngx_http.c
@@ -1927,6 +1927,7 @@
 #if (NGX_HTTP_V2)
         addrs6[i].conf.http2 = addr[i].opt.http2;
 #endif
+        addrs6[i].conf.proxy_protocol = addr[i].opt.proxy_protocol;
 
         if (addr[i].hash.buckets == NULL
             && (addr[i].wc_head == NULL