fix python2 corner-case in torch.distributed.launch (#20996)
Summary:
Small fix for the comment raised in https://github.com/pytorch/pytorch/commit/4cf76574b958b41ae1df7fba6e87af101414549e#r33134850
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20996
Differential Revision: D15991510
Pulled By: pietern
fbshipit-source-id: 4e5a35864b5a4ec9402aa83a19c4a3ba0df2f01f
