sys user split: first pass updating Settings

Update various places in Settings to use "admin" ueser flag
instead of checking user id "0".  This should be no-op in
single user mode since the only admin user would be user 0.
In split system user mode, this will correctly ACL admin
user instead of non-interactive system user.

Bug: 19913735
Change-Id: Ida4d59c5f689ea0dc34b3b3ff0822b087fa0afd6

src/com/android/settings/PrivacySettings.java

@@ -71,8 +71,9 @@ public class PrivacySettings extends SettingsPreferenceFragment implements Index
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        // Don't allow any access if this is a secondary user
-        mEnabled = Process.myUserHandle().isOwner();
+        // Don't allow any access if this is not an admin user.
+        // TODO: backup/restore currently only works with owner user b/22760572
+        mEnabled = UserManager.get(getActivity()).isAdminUser();
         if (!mEnabled) {
             return;
         }