merge origin

Former-commit-id: 604cab376a780fac2e880f4167570344dbb6d1c3

oneflow/core/operator/roi_pooling_op.h

@@ -15,8 +15,6 @@ class RoIPoolingOp final : public Operator {
 
   void InitFromOpConf() override;
 
-  bool NeedOutWhenBackward() const override { return false; }
-
   void InferBlobDescs(std::function<BlobDesc*(const std::string&)> GetBlobDesc4BnInOp,
                       const ParallelContext* parallel_ctx) const override;
 };