Throw exception when foxi is not checked out (#17477)
Summary:
Add check and provide useful warning/error information to user if foxi is not checked out.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/17477
Reviewed By: zrphercule
Differential Revision: D14212896
Pulled By: houseroad
fbshipit-source-id: 557247d5d8fdc016b1c24c2a21503e59f874ad09
