Rework copyDirectoryContent
Rework copyDirectoryContent

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