Warn users when eval is skipped (#624)
Warn users when eval is skipped (#624)

Summary:
Fix for #620 & #293.
Pull Request resolved: https://github.com/facebookresearch/Detectron/pull/624

Reviewed By: ir413

Differential Revision: D9574052

Pulled By: rbgirshick

fbshipit-source-id: f44cea71e5cf6e613d319322db62a60ecb814a75

facebookresearch/Detectron,facebookresearch/Detectron,facebookresearch/Detectron