Fixed -Wunused-parameter warnings

plugins/feature/afc/afc.cpp

@@ -259,6 +259,7 @@ int AFC::webapiRun(bool run,
     SWGSDRangel::SWGDeviceState& response,
     QString& errorMessage)
 {
+    (void) errorMessage;
     getFeatureStateStr(*response.getState());
     MsgStartStop *msg = MsgStartStop::create(run);
     getInputMessageQueue()->push(msg);