Fix various errors and warnings
Fix various errors and warnings

Summary: Fix various errors that Flipper was complaining about in Watch plugin

Reviewed By: ankursadhoo

Differential Revision: D19168777

fbshipit-source-id: eefb98818ddb0da78de1daf2d67045cb90cd90aa

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper