GitLab

Summary:
Pull Request resolved: https://github.com/facebookresearch/d2go/pull/436

Renaming `model_ema.py` to `ema.py` (as `modeling` is already in the folder name. Fixing dependencies after rename

Reviewed By: wat3rBro

Differential Revision: D41685115

fbshipit-source-id: 006999a020a901ea8be4b71e072d688bd36cdce2