Fix bug introduced in a recent commit
Fix bug introduced in a recent commit

Summary:
This is introduced in https://github.com/caffe2/caffe2/commit/8539a1e78b7fd8aa92b08a8f24b2b0f7978bf5a5 - vector<float> should not be used in Tensor shape inference.
Closes https://github.com/caffe2/caffe2/pull/1393

Reviewed By: akyrola

Differential Revision: D6181075

Pulled By: Yangqing

fbshipit-source-id: 002144a137148b5b16118d0c123132890e8d325a

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