Summary:
This diff cleans up several Android Makefiles which we're not using anymore
as they've been replaced by CMake files.
There are still 3 Makefiles left, which I'm aiming to remove in the near future.
Changelog:
[Internal] [Changed] - Remove unused Makefiles from React Native core
Reviewed By: javache
Differential Revision: D36660902
fbshipit-source-id: 8afffac74d493616b0f9414567821cd69f4ef803