sanity checks for data parallel model
sanity checks for data parallel model

Summary: To help dgponinath, and people in general: check that params don't have duplicate entries.

Differential Revision: D4872132

fbshipit-source-id: 1cca1237fda771eb270227f452ecae0f912d7a33

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