[Caffe2] Fix double map lookup in operator_schema.h
[Caffe2] Fix double map lookup in operator_schema.h

[Caffe2] Fix double map lookup in `operator_schema.h`.

xzturn/caffe2,xzturn/caffe2,xzturn/caffe2,xzturn/caffe2,xzturn/caffe2,caffe2/caffe2