Remove compile-time warning for serial connection plugin.

git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@2122 ebee16cc-31ac-478f-84a7-5cbb03baadba

ground/src/plugins/serialconnection/serialplugin.cpp

@@ -103,6 +103,7 @@ QIODevice *SerialConnection::openDevice(const QString &deviceName)
 
 void SerialConnection::closeDevice(const QString &deviceName)
 {
+    Q_UNUSED(deviceName);
     //we have to delete the serial connection we created
     if (serialHandle){
         serialHandle->close ();