Observer for GPS is never added back.

mSettingsObserver will be added only once  to mContentQueryMap on first start,
but if you bring activity back to top, it will not be added any more.

Signed-off-by: Vladimir Baryshnikov <vovkab@gmail.com>

src/com/android/settings/LocationSettings.java

@@ -123,8 +123,9 @@ public class LocationSettings extends SettingsPreferenceFragment
                     updateLocationToggles();
                 }
             };
-            mContentQueryMap.addObserver(mSettingsObserver);
         }
+
+        mContentQueryMap.addObserver(mSettingsObserver);
     }
 
     @Override