Fix _apply in nn.Module (#15305)
Summary:
Fixes an issue that arose from https://github.com/pytorch/pytorch/pull/13481 where `.shared_memory()` couldn't be called. Effectively undoes all changes to `nn.Module` from that PR and solve the relevant problem in a different way (the goal was to be able to call `._apply()` on the Python wrapper for a C++ module).
soumith
Pull Request resolved: https://github.com/pytorch/pytorch/pull/15305
Differential Revision: D13493937
Pulled By: goldsborough
fbshipit-source-id: 4cb8687f90fc8709a536c5e7eacd0dc8edf6f750
