fix missing DPM .values() and .keys() to viewvalues() and viewkeys()
fix missing DPM .values() and .keys() to viewvalues() and viewkeys()

Summary: Reported by SImon Layton from NVIDIA: we had a couple of py3-incompatible expresions in data_parallel_model

Reviewed By: azzolini

Differential Revision: D6349447

fbshipit-source-id: a09feb69396be43296400591a3bfed5b8c370b0d

davinwang/caffe2,Yangqing/caffe2,sf-wind/caffe2,sf-wind/caffe2,xzturn/caffe2,xzturn/caffe2,Yangqing/caffe2,Yangqing/caffe2,Yangqing/caffe2,pietern/caffe2,sf-wind/caffe2,sf-wind/caffe2,sf-wind/caffe2,xzturn/caffe2,pietern/caffe2,davinwang/caffe2,xzturn/caffe2,pietern/caffe2,pietern/caffe2,davinwang/caffe2,caffe2/caffe2,davinwang/caffe2,Yangqing/caffe2,xzturn/caffe2,davinwang/caffe2,pietern/caffe2