Fix unexpected language changes on SIM card insertion.

There are two separate issues here that need to be fixed, both
boil down to the fact that adding an imperative (userSetLocale)
to the Configuration is a bad idea. Because of this:

- We'd never persist the first user set configuration if it was en_US,
  because of an erroneous call to Configuration.setLocale.

- ActivityManager.getConfiguration would sometimes return a
  Configuration with userSetLocale == true, which means callers with
  the right permissions would inadvertently persist a locale they didn't
  want to persist.

bug: 18879010

Change-Id: Id330ffde9d2a6e516fd60edc33f5529df719c634