pytorch

a8edc2b5 - Add sanity checks for NCCL detection.

Add sanity checks for NCCL detection. Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/22926 Differential Revision: D16546369 Pulled By: colesbury fbshipit-source-id: 56f7ef4476e586dee19366fdb720085d1c2f2027