Hygiene: Remove redundant ANDROID_HOME setting
Hygiene: Remove redundant ANDROID_HOME setting

SDK installation is managed by the Jenkins emulator plugin for our
periodic job, which uses it; no need to set it here.

Change-Id: I134dd00a76c09b559c6f333bddfde66482166abb

dbrant/apps-android-wikipedia,wikimedia/apps-android-wikipedia,wikimedia/apps-android-wikipedia,dbrant/apps-android-wikipedia,wikimedia/apps-android-wikipedia,wikimedia/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia