Hotfix crash in OSX engine dialog.

This is not really a fix, just some quick hack
to make ardour start at all if there’s no prior
CoreAudio EngineState in the config.

libs/backends/wavesaudio/wavesapi/devicemanager/WCMRCoreAudioDeviceManager.cpp

@@ -115,6 +115,7 @@ WCMRCoreAudioDevice::WCMRCoreAudioDevice (WCMRCoreAudioDeviceManager *pManager,
     
     m_CurrentSamplingRate = DEFAULT_SR;
     m_CurrentBufferSize = DEFAULT_BUFFERSIZE;
+    m_DefaultBufferSize = DEFAULT_BUFFERSIZE;
     m_StopRequested = true;
     m_pInputData = NULL;