Add Override anntation for TetheringConnector.setPreferTestNetworks

Test: TH
Change-Id: Idfaca3cb59580ffe4ee194466ad2ba8f47d8fac4
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringService.java b/Tethering/src/com/android/networkstack/tethering/TetheringService.java
index d3d2962..4d3fd75 100644
--- a/Tethering/src/com/android/networkstack/tethering/TetheringService.java
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringService.java
@@ -200,6 +200,7 @@
             } catch (RemoteException e) { }
         }
 
+        @Override
         public void setPreferTestNetworks(boolean prefer, IIntResultListener listener) {
             if (!checkCallingOrSelfPermission(NETWORK_SETTINGS)) {
                 try {