Android: Remove usage of QObject::tr()

Change-Id: I948d9fc36aa52d2d247a84b5d9b2cf949b93387d
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>