Track changes to locale management.

For MccTable : use persist.sys.locale to detect whether the user
has set a locale instead of persist.sys.locale.language / region.

For CatService : use Locale.getDefault, which will always return
the current locale. There's no need to rely on a system property.

bug: 17691569
Change-Id: Ic0f39067a04e4cb762848a6bd81a6ee97a392126