NFSv4: Don't call update_changeattr() unless the unlink is successful

If the unlink wasn't successful, then the directory has presumably not
changed.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4proc.c

@@ -4125,6 +4125,7 @@ static int nfs4_proc_unlink_done(struct rpc_task *task, struct inode *dir)
 	if (nfs4_async_handle_error(task, res->server, NULL,
 				    &data->timeout) == -EAGAIN)
 		return 0;
+	if (task->tk_status == 0)
 		update_changeattr(dir, &res->cinfo);
 	return 1;
 }