Set ANDROID_SDK and ANDROID_HOME for Travis build

Summary: Travis builds are failing due to ANDROID_SDK not being set.  So we set both it and ANDROID_HOME to where homebrew should have created a link to the installation.

Reviewed By: emilsjolander

Differential Revision: D4571703

fbshipit-source-id: a6dc4eb07006dc8baefb6ca938111ff256c6f018

Author: Robert Spencer

.travis.yml

@@ -57,6 +57,8 @@ before_install:
       export JAVA_HOME=$(/usr/libexec/java_home -v 1.8);
       export PATH=$JAVA_HOME/bin:$PATH;
       brew install android-sdk;
+      export ANDROID_SDK=/usr/local/opt/android-sdk
+      export ANDROID_HOME=/usr/local/opt/android-sdk
     fi
 
 script: