Throw if someone tries to torch.save() quantized modules (#26828)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26828
Pickle serialization for quantized modules is currently broken by https://github.com/pytorch/pytorch/issues/24045, so let's be loud and fail if the user tries to do it
Test Plan: Imported from OSS
Differential Revision: D17579127
Pulled By: jamesr66a
fbshipit-source-id: 3deccac7e4590c6f648f22bb79c57badf3bf0487
