confile: cleanup clr_config_net_veth_ipv6_route()

src/lxc/confile.c

@@ -5517,7 +5517,7 @@ static int clr_config_net_veth_ipv6_route(const char *key,
 	struct lxc_list *cur, *next;
 
 	if (!netdev)
-		return -1;
+		return ret_errno(EINVAL);
 
 	lxc_list_for_each_safe(cur, &netdev->priv.veth_attr.ipv6_routes, next) {
 		lxc_list_del(cur);