Revert D26753571: [pytorch][PR] add submodules to sys.modules so their attributes can be pickled
Test Plan: revert-hammer
Differential Revision:
D26753571 (https://github.com/pytorch/pytorch/commit/fbf9745c85b6b50fec0156ff1f877a1209f76779)
Original commit changeset: 2bda03bab39f
fbshipit-source-id: cc9cc4f508af122b0fdec7f8475343bd9badb9db
