Android: fix zipAlign location.

Stating with android tools v23, the zipAlign tool was moved from
<android_sdk>/tools to <android_sdk>/build-tools/<build_tools_version>.

Task-number:QTBUG-40481
Change-Id: Id9207b6e382b0e79522d9fc529453ccd39aebe0d
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>