Fixing bugs 2577511 and 2581920.

Making sure that the language, country, and variant defaults are always
set to something to ensure that there won't be an NPE.
Dismissing the ListPreference dialogs before a rotation to avoid list
data corruption caused by the list being displayed while its data is
being re-initialized.

Change-Id: Iecdb3b4d415542dc8a4db162c930e6a6570a55f2