Fix outdated comments.
Fix outdated comments.

See #210.

bgamari/shaking-up-ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,izgzhen/hadrian,sdiehl/ghc,sdiehl/ghc,snowleopard/hadrian,snowleopard/shaking-up-ghc