Reverted build tools version to fix CircleCI
Reverted build tools version to fix CircleCI

Summary:
We've switched CircleCI to use Ubuntu 14.04 but this causes Android NDK problems since it is not installed per default (see https://discuss.circleci.com/t/android-ndk-installation-and-configuration-on-circleci/3816).
We're reverting back to Ubuntu 12.04, which only has Android Build Tools 23.0.2 - so we have to revert to a supported version.

Reviewed By: kirwan

Differential Revision: D3488154

fbshipit-source-id: a08ac4be41106d0f2ee042c2b48163fec469d0b7

xjy2061/NovaImageLoader,facebook/fresco,s1rius/fresco,desmond1121/fresco,wstczlt/fresco,xjy2061/NovaImageLoader,MaTriXy/fresco,0mok/fresco,s1rius/fresco,MaTriXy/fresco,MaTriXy/fresco,HKMOpen/fresco,wstczlt/fresco,0mok/fresco,s1rius/fresco,MaTriXy/fresco,facebook/fresco,facebook/fresco,wstczlt/fresco,facebook/fresco,xjy2061/NovaImageLoader,s1rius/fresco,0mok/fresco,desmond1121/fresco,wstczlt/fresco,HKMOpen/fresco,facebook/fresco,desmond1121/fresco,desmond1121/fresco,HKMOpen/fresco,MaTriXy/fresco,desmond1121/fresco,HKMOpen/fresco,xjy2061/NovaImageLoader,wstczlt/fresco,facebook/fresco,0mok/fresco,0mok/fresco,xjy2061/NovaImageLoader