message: fix RecordWriter Flush only work when ZlibCompressed
diff: @@ -125,11 +125,8 @@ Status RecordWriter::Flush() {
  return Status(::tensorflow::error::FAILED_PRECONDITION,
  "Writer not initialized or previously closed");
  }
  - if (IsZlibCompressed(options_)) {
  return dest_->Flush();
  }
  - return Status::OK();
  -}
  } // namespace io
  } // namespace tensorflow
  