CoreAudio: Use the real default audio device for QSoundEffect

There is an assumption in QtMultimedia that the first audio device
returned by QAudioDeviceInfo::availableDevices is the default device, so
we must make an effor to make sure this is true.  This commit should fix
the issue on OS X.

Task-number: QTBUG-36638
Change-Id: Id388d7218b465cb29d826f46ee825e982c5f7ffc
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>
AVFoundation: Remove debug code

Some debug code made it into the released code, so each time you used
the QWidget based video player the terminal would print data about the
window frame size.

Change-Id: I86eb00ce5edb23b7a2abf6a63893cd17aaeb0ee3
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>