Fix leaking IntentReceiver in SettingsActivity

We added a new IntentReceiver to notice users being added and
removed, but missed unregistering it where appropriate.

Change-Id: I3ca1d7c8916870066dda34b830e100948dd4481c

src/com/android/settings/SettingsActivity.java

@@ -778,6 +778,7 @@ public class SettingsActivity extends SettingsDrawerActivity
     protected void onPause() {
         super.onPause();
         unregisterReceiver(mBatteryInfoReceiver);
+        unregisterReceiver(mUserAddRemoveReceiver);
         mDynamicIndexableContentMonitor.unregister();
     }