message: nydus-snapshotter: fix recreate daemon config/socket dir
  when create multiple containers with same image, nydus-snapshotter will
  create daemon config/socket dir per container, most of them can not be
  deleted even though the image is deleted.
diff: @@ -344,6 +344,10 @@ func (fs *filesystem) createNewDaemon(snapshotID string, imageID string) (*daemo
  d *daemon.Daemon
  err error
  )
  + d, _ = fs.manager.GetBySnapshotID(snapshotID)
  + if d != nil {
  + return nil, errdefs.ErrAlreadyExists
  + }
  customMountPoint := filepath.Join(fs.SnapshotRoot(), snapshotID, "mnt")
  if d, err = daemon.NewDaemon(
  daemon.WithSnapshotID(snapshotID),
  @@ -373,7 +377,10 @@ func (fs *filesystem) createSharedDaemon(snapshotID string, imageID string) (*da
  d *daemon.Daemon
  err error
  )
  -
  + d, _ = fs.manager.GetBySnapshotID(snapshotID)
  + if d != nil {
  + return nil, errdefs.ErrAlreadyExists
  + }
  sharedDaemon, err = fs.getSharedDaemon()
  if err != nil {
  return nil, err
  