Ensure all active Device Admins are listed.

Bug: 9074296
(cherry picked from commit d14258e5)

Conflicts:
	src/com/android/settings/DeviceAdminSettings.java

Changes made to make the cherry-pick apply:
* Dropped PackageManager.GET_DISABLED_UNTIL_USED_COMPONENTS in the
  PackageManager.queryBroadcastReceivers invocation. The above
  flag was introduced in API Level 18.

Change-Id: I65596c49bedad7e39ceb1785859c129db1e3e6d7