Revert "[Settings] Convert to getSystemService(Class<T>)"

Revert submission 1645152-getSystemService(Class<T>)

Reason for revert: Fix JUnit test failure
Reverted Changes:
I1b4812044:[Settings] Convert to getSystemService(Class<T>)
I278951c24:[Settings] Support getSystemService(Class<T>)

Change-Id: I864a40f82ba9cb4170900ac0c1d77f781b17341f

src/com/android/settings/wifi/p2p/WifiP2pSettings.java

@@ -200,7 +200,7 @@ public class WifiP2pSettings extends DashboardFragment
     public void onActivityCreated(Bundle savedInstanceState) {
         final Activity activity = getActivity();
         if (mWifiP2pManager == null) {
-            mWifiP2pManager = getSystemService(WifiP2pManager.class);
+            mWifiP2pManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
         }
 
         if (mWifiP2pManager != null) {