[Minor] Don't add User-Agent in HTTP replies

src/libutil/http_connection.c

@@ -1995,7 +1995,7 @@ rspamd_http_connection_write_message_common (struct rspamd_http_connection *conn
 		}
 	}
 
-	if (priv->ctx->config.user_agent) {
+	if (priv->ctx->config.user_agent && conn->type == RSPAMD_HTTP_CLIENT) {
 		rspamd_http_message_add_header (msg, "User-Agent",
 				priv->ctx->config.user_agent);
 	}