GitLab

Summary:
Pull Request resolved: https://github.com/facebookresearch/d2go/pull/261

X-link: https://github.com/facebookresearch/mobile-vision/pull/71

`is_oss` and `fb_overwritable` are also needed in `mobile_cv`, move them from d2go.

Reviewed By: zhanghang1989

Differential Revision: D36655821

fbshipit-source-id: 421c4d22d4c4620678908fe13d6e47ab39604ae7