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/WifiConfigInfo.java

@@ -38,7 +38,7 @@ public class WifiConfigInfo extends Activity {
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
-        mWifiManager = getSystemService(WifiManager.class);
+        mWifiManager = (WifiManager) getSystemService(WIFI_SERVICE);
         setContentView(R.layout.wifi_config_info);
         mConfigList = (TextView) findViewById(R.id.config_list);
     }