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

This reverts commit d5ccde31a8.

Reason for revert: failure on test cases

Change-Id: I0a179a6ebb5ef1dec566ce6e8facd5f3b82d7c8a

src/com/android/settings/wifi/UseOpenWifiPreferenceController.java

@@ -51,7 +51,7 @@ public class UseOpenWifiPreferenceController extends TogglePreferenceController
         super(context, KEY_USE_OPEN_WIFI_AUTOMATICALLY);
         mContentResolver = context.getContentResolver();
         mNetworkScoreManager =
-                context.getSystemService(NetworkScoreManager.class);
+                (NetworkScoreManager) context.getSystemService(Context.NETWORK_SCORE_SERVICE);
         mSettingObserver = new SettingObserver();
         updateEnableUseWifiComponentName();
         checkForFeatureSupportedScorers();