proper deletion ordering

delete central file store first, then delete local cache

weed/filer2/filer_delete_entry.go

@@ -65,6 +65,7 @@ func (f *Filer) doBatchDeleteFolderMetaAndData(ctx context.Context, entry *Entry
 		}
 		if lastFileName == "" && !isRecursive && len(entries) > 0 {
 			// only for first iteration in the loop
+			glog.Errorf("deleting a folder %s has children: %+v", entry.FullPath, entries)
 			return nil, fmt.Errorf("fail to delete non-empty folder: %s", entry.FullPath)
 		}