Update README.race.md
Update README.race.md

Summary: Pull Request resolved: https://github.com/pytorch/fairseq/pull/1155

Differential Revision: D17509762

Pulled By: myleott

fbshipit-source-id: 4de535289c1f35abff0d8142d8580f3ede039f47

pytorch/fairseq,pytorch/fairseq,pytorch/fairseq