message: Remove unused CreateNode()
diff: @@ -126,11 +126,6 @@ class LMDBDatasetOp : public DatasetOpKernel {
  }
  protected:
  - std::shared_ptr<model::Node> CreateNode(
  - IteratorContext* ctx, model::Node::Args args) const override {
  - return model::MakeSourceNode(std::move(args));
  - }
  -
  Status SaveInternal(IteratorStateWriter* writer) override {
  return errors::Unimplemented(
  "Checkpointing is currently not supported for LMDBDataset.");
  