Janic Duplessis 5353d39172 Remove unused native iOS sticky headers implementation
Summary:
Remove the native iOS sticky headers implementation that has been replaced by the js Animated one. Also remove a line in JS that made sure we passed null to native so it did not use the native implementation.

**Test plan**
Made sure there were no more mentions of sticky / header in native ScrollView related code.
Tested that sticky headers still work :o
Closes https://github.com/facebook/react-native/pull/12696

Differential Revision: D4657391

Pulled By: ericvicenti

fbshipit-source-id: 16324a45ca4ce5cd143293c61394a0fa7ad0c4a1
2017-03-05 14:21:40 -08:00
..
2017-02-28 14:15:57 -08:00