remove unused variable
remove unused variable

Summary: Oops, I left an unused variable here. Let's get rid of that!

Reviewed By: enosair

Differential Revision: D6468223

fbshipit-source-id: 27cc0900b330f056c5b5585a136fb46f5830cf81

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