[Bugfix] fix snapshotter variable check in ContainerWithCheckpoint

Signed-off-by: lujinda <q8886888@qq.com>
Signed-off-by: jinda.ljd <jinda.ljd@alibaba-inc.com>

client/container_restore_opts.go

@@ -50,7 +50,7 @@ func WithRestoreImage(ctx context.Context, id string, client *Client, checkpoint
 			return ErrImageNameNotFoundInIndex
 		}
 		snapshotter, ok := index.Annotations[checkpointSnapshotterNameLabel]
-		if !ok || name == "" {
+		if !ok || snapshotter == "" {
 			return ErrSnapshotterNameNotFoundInIndex
 		}
 		i, err := client.GetImage(ctx, name)