Update proxy_host.conf by replace $host:$server with $http_host

Author: constanine

backend/templates/proxy_host.conf

@@ -56,7 +56,7 @@ proxy_http_version 1.1;
     {% if allow_websocket_upgrade == 1 or allow_websocket_upgrade == true %}
     proxy_set_header Upgrade $http_upgrade;
     proxy_set_header Connection $http_connection;
-    proxy_set_header Host $host:$server_port;
+    proxy_set_header Host $http_host;
     proxy_http_version 1.1;
     {% endif %}