Allow factory reset in carrier demo mode

Bug: 34341567
Test: manual - in carrier demo mode, go to Settings > Backup and
Reset > Factory data reset > Reset phone > Erase everything and
this entire path is viewable.

Change-Id: Ia5491765241adad97ecdb0a5bfd86a8371b8e4fe

src/com/android/settings/SettingsActivity.java

@@ -968,7 +968,8 @@ public class SettingsActivity extends SettingsDrawerActivity
 
         // Enable/disable backup settings depending on whether the user is admin.
         setTileEnabled(new ComponentName(packageName,
-                BackupSettingsActivity.class.getName()), true, isAdmin);
+                BackupSettingsActivity.class.getName()), true,
+                isAdmin || Utils.isCarrierDemoUser(this));
         setTileEnabled(new ComponentName(packageName,
                 "com.android.settings.BackupResetDashboardAlias"), true, isAdmin);