Unused variables in neural net classes and functions (#50100)
Summary:
These unused variables were identified by [pyflakes](https://pypi.org/project/pyflakes/). They can be safely removed to simplify the code and possibly improve performance.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50100
Reviewed By: ezyang
Differential Revision: D25797764
Pulled By: smessmer
fbshipit-source-id: ced341aee692f429d2dcc3a4ef5c46c8ee99cabb
