MXNet Release-1.2.1 patch (#11548)
MXNet Release-1.2.1 patch (#11548)

* Fix save_params warning mesage (#11532)

* Update block.py (#11540)

nit fix

TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet