Fix np.load failure in python3 when loading numerical data serialized in python2
Fix np.load failure in python3 when loading numerical data serialized in python2

https://travis-ci.org/onnx/onnx-caffe2/jobs/278346399#L1998

onnx/onnx,onnx/onnx,onnx/onnx,onnx/onnx