Summary: Check that the WS state is set to OPEN before trying to close it when the ```websocketFailed``` event fires. Otherwise the app throws an error at the Android level.
Fixes#3346
Closes https://github.com/facebook/react-native/pull/3347
Reviewed By: @svcscm
Differential Revision: D2535807
Pulled By: @mkonicek
fb-gh-sync-id: bb70c551ea2e582cfaa80139a265dbbca6d990d2