virtio-9p-proxy: Fix sockfd leak

If connect() in connect_namedsocket() return false, the sockfd will leak.
Plug it.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>

hw/9pfs/virtio-9p-proxy.c

@@ -1112,6 +1112,7 @@ static int connect_namedsocket(const char *path)
     size = strlen(helper.sun_path) + sizeof(helper.sun_family);
     if (connect(sockfd, (struct sockaddr *)&helper, size) < 0) {
         fprintf(stderr, "socket error\n");
+        close(sockfd);
         return -1;
     }