Summary: I have disected lint warnings fixes to several PRs. This one fixes lint warnings under Libraries/Utility path.
Closes https://github.com/facebook/react-native/pull/4444
Reviewed By: svcscm
Differential Revision: D2705303
Pulled By: spicyj
fb-gh-sync-id: c745ac62cbff30d6bb9478a1d2465fe56b305f0c