Fallback to SharedPreferences$Editor.commit() when no apply() exists.

Gingerbread widened the SharedPreferences.Editor interface, adding an
apply() method.  Most people don't implement this interface
themselves, but a couple apps do.

A few spots in the core framework take a SharedPreferences[.Editor]
from apps, which might be a pre-Gingerbread implementation without an
apply() method.  This patch makes sure we never depend on the presence
of an apply() method, falling back to commit() if apply() isn't
available.

Change-Id: I32693ac9227a60b694526a26a30234fb17a40581