Always use the LocalePicker's preferred locale names.

Without this change we have the odd situation where LocalePicker goes out of
its way to avoid saying certain things but then -- as long as there's more than
one locale for a given language -- Settings would happily report the name we'd
been avoiding. (Either because it's too specific or because it's too sensitive.)

Also remove the unused bit-rotted duplicate of the blacklist; even if we needed
to access that list directly, we should use LocalePicker's copy.

Bug: 17150708
Change-Id: I9bfa0bf9a82bebd29ba45f4cbeaabb4e78570779