message: nydusd: do not print error message when exiting
  Do not print error message when exiting, that's expected instead of
  error.
diff: @@ -113,10 +113,11 @@ impl FuseServer {
  let _ebadf = Error::from_raw_os_error(libc::EBADF);
  loop {
  - if let Some((reader, writer)) = self.ch.get_request().map_err(|e| {
  - warn!("get fuse request failed: {:?}", e);
  - Error::from_raw_os_error(libc::EINVAL)
  - })? {
  + if let Some((reader, writer)) = self
  + .ch
  + .get_request()
  + .map_err(|e| eother!(format!("failed to get fuse request from /dev/fuse, {}", e)))?
  + {
  if let Err(e) =
  self.server
  .handle_message(reader, writer.into(), None, Some(metrics_hook))
  @@ -255,8 +256,7 @@ impl FusedevDaemon {
  let thread = thread::Builder::new()
  .name("fuse_server".to_string())
  .spawn(move || {
  - if let Err(err) = s.svc_loop(&inflight_op) {
  - warn!("fuse server exits with err: {:?}, exiting daemon", err);
  + if let Err(_err) = s.svc_loop(&inflight_op) {
  if let Err(err) = waker.wake() {
  error!("fail to exit daemon, error: {:?}", err);
  }
  