Localization: do not use private ICU APIs

Instead of using private ICU APIs for checking, if the ICU's version
has been updated, use the android sdk version.

It is safe to assume, that ICU version does not change randomly and if
then only on major Android version upgrades.

Change-Id: Ia348a5597aa472d44b766b869a31a3935723f210
Signed-off-by: Alexander Martinz <amartinz@shiftphones.com>