filer: avoid deletion error when item is not found

weed/server/filer_grpc_server.go

@@ -326,7 +326,7 @@ func (fs *FilerServer) DeleteEntry(ctx context.Context, req *filer_pb.DeleteEntr
 
 	err = fs.filer.DeleteEntryMetaAndData(ctx, util.JoinPath(req.Directory, req.Name), req.IsRecursive, req.IgnoreRecursiveError, req.IsDeleteData, req.IsFromOtherCluster, req.Signatures)
 	resp = &filer_pb.DeleteEntryResponse{}
-	if err != nil {
+	if err != nil && err != filer_pb.ErrNotFound {
 		resp.Error = err.Error()
 	}
 	return resp, nil