Avoid double bucket validation in DeleteObjectHandler (#6720)

On a heavily loaded server, getBucketInfo() becomes slow,
one can easily observe deleting an object causes many
additional network calls.

This PR is to let the underlying call return the actual
error and write it back to the client.

cmd/xl-v1-utils.go

@@ -305,7 +305,7 @@ func readXLMeta(ctx context.Context, disk StorageAPI, bucket string, object stri
 	// Reads entire `xl.json`.
 	xlMetaBuf, err := disk.ReadAll(bucket, path.Join(object, xlMetaJSONFile))
 	if err != nil {
-		if err != errFileNotFound {
+		if err != errFileNotFound && err != errVolumeNotFound {
 			logger.GetReqInfo(ctx).AppendTags("disk", disk.String())
 			logger.LogIf(ctx, err)
 		}