Add dependency Python packages for onnx-caffe2
Add dependency Python packages for onnx-caffe2

Summary:
onnx-caffe2 requires some more Python packages in order to run its tests.
Closes https://github.com/caffe2/caffe2/pull/1956

Reviewed By: bddppq

Differential Revision: D6985654

Pulled By: yinghai

fbshipit-source-id: 06d4ec95729b09cdd1bc7e096ecf6680124070cd

xzturn/caffe2,Yangqing/caffe2,caffe2/caffe2,Yangqing/caffe2,xzturn/caffe2,xzturn/caffe2,xzturn/caffe2,Yangqing/caffe2,Yangqing/caffe2,xzturn/caffe2,Yangqing/caffe2