Fix QtMultimedia test to not fail when no devices were found.
Fix QtMultimedia test to not fail when no devices were found.

Reviewer: Renato Araújo <16af9705e5a16d85aed275f2f9e8171326ec17f6@openbossa.org>
          Marcelo Lira <marcelo.lira@openbossa.org>

RobinD42/pyside,BadSingleton/pyside2,IronManMark20/pyside2,enthought/pyside,M4rtinK/pyside-bb10,RobinD42/pyside,qtproject/pyside-pyside,pankajp/pyside,pankajp/pyside,M4rtinK/pyside-bb10,gbaty/pyside2,M4rtinK/pyside-android,M4rtinK/pyside-bb10,IronManMark20/pyside2,M4rtinK/pyside-bb10,M4rtinK/pyside-android,RobinD42/pyside,pankajp/pyside,gbaty/pyside2,qtproject/pyside-pyside,M4rtinK/pyside-android,IronManMark20/pyside2,PySide/PySide,enthought/pyside,PySide/PySide,gbaty/pyside2,RobinD42/pyside,BadSingleton/pyside2,PySide/PySide,M4rtinK/pyside-android,M4rtinK/pyside-bb10,PySide/PySide,BadSingleton/pyside2,enthought/pyside,enthought/pyside,pankajp/pyside,enthought/pyside,M4rtinK/pyside-bb10,RobinD42/pyside,PySide/PySide,gbaty/pyside2,pankajp/pyside,RobinD42/pyside,BadSingleton/pyside2,BadSingleton/pyside2,qtproject/pyside-pyside,RobinD42/pyside,qtproject/pyside-pyside,qtproject/pyside-pyside,M4rtinK/pyside-android,IronManMark20/pyside2,gbaty/pyside2,M4rtinK/pyside-android,IronManMark20/pyside2,enthought/pyside,enthought/pyside