Fix lxc-console hang

The variable 'descr' is mistakenly covered with 'descr_console'.

Signed-off-by: LiFeng <lifeng68@huawei.com>

src/lxc/start.c

@@ -540,6 +540,8 @@ int lxc_poll(const char *name, struct lxc_handler *handler)
 			ERROR("Failed to add console handlers to console mainloop");
 			goto out_mainloop_console;
 		}
+
+		handler->conf->console.descr = &descr;
 	}
 
 	ret = lxc_cmd_mainloop_add(name, &descr, handler);