Update usage of API DPM.getWifiMacAddress.

Bug: 27532280
Change-Id: I6d4ee02e622dd857c09d60ae630c469c6fb5f07b

Author: Sudheer Shanka

app/src/main/java/com/afwsamples/testdpc/policy/PolicyManagementFragment.java

@@ -952,7 +952,7 @@ public void onClick(DialogInterface dialogInterface, int i) {
      * Shows a message box with the device wifi mac address.
      */
     private void showWifiMacAddress() {
-        final String macAddress = mDevicePolicyManager.getWifiMacAddress();
+        final String macAddress = mDevicePolicyManager.getWifiMacAddress(mAdminComponentName);
         final String message = macAddress != null ? macAddress
                 : getResources().getString(R.string.show_wifi_mac_address_not_available_msg);
         new AlertDialog.Builder(getActivity())