start: change log level

src/lxc/start.c

@@ -1798,7 +1798,7 @@ static int lxc_spawn(struct lxc_handler *handler)
 
 		ret = lxc_netns_set_nsid(handler->nsfd[LXC_NS_NET]);
 		if (ret < 0)
-			SYSERROR("Failed to allocate new network namespace id");
+			SYSWARN("Failed to allocate new network namespace id");
 		else
 			TRACE("Allocated new network namespace id");
 	}