Don't request metadata when listing objects

While some implementations may support it, it appears that most don't,
and some may in fact return an error if it is requested.

We already stat the object to get the metadata anyway, so this was
unnecessary if harmless on most implementations.

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>

pkg/etcd/s3.go

@@ -360,9 +360,8 @@ func (s *S3) listSnapshots(ctx context.Context) (map[string]snapshotFile, error)
 	defer cancel()
 
 	opts := minio.ListObjectsOptions{
-		Prefix:       s.config.EtcdS3Folder,
-		Recursive:    true,
-		WithMetadata: true,
+		Prefix:    s.config.EtcdS3Folder,
+		Recursive: true,
 	}
 
 	objects := s.client.ListObjects(ctx, s.config.EtcdS3BucketName, opts)