Migrate build_adagrad to python directory
Migrate build_adagrad to python directory

Summary:
The change migrates build_adagrad function to the open source python directory.
Depends on D4547016.

Reviewed By: salexspb

Differential Revision: D4551871

fbshipit-source-id: cb68d9b2a723b0f069c8a24cfa3062f1e676c016

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