Update Travis config for latest Android SDK release.
Update Travis config for latest Android SDK release.

A thousand CI builds cry out whenever Google updates this.

prateeknitish391/demo,mray19027/openxc-android,petemaclellan/openxc-android,prateeknitish391/demo,petemaclellan/openxc-android,ChernyshovYuriy/openxc-android,msowka/openxc-android,dhootha/openxc-android,msowka/openxc-android,prateeknitish391/demo,mray19027/openxc-android,openxc/openxc-android,openxc/openxc-android,ChernyshovYuriy/openxc-android,dhootha/openxc-android