Summary:
Pull Request resolved: https://github.com/facebookresearch/pytext/pull/1337

"Normal" python needs the __init__.py file per folder for it to be a python package.

Reviewed By: mwu1993

Differential Revision: D21242499

fbshipit-source-id: 159d72ab0b0341bee5e66ff2857a6ad267d941b9