remove non-existing blobs from output_schema in layer_model_instantiator
remove non-existing blobs from output_schema in layer_model_instantiator

Summary: In some cases (for example, when include_tags option is used) output_schema contains blobs that aren't produced by the generated net. In this case we want to filter them from output_schema as well.

Differential Revision: D5120115

fbshipit-source-id: f98ea3f747589390b039d1e1987becec3980634c

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