Fix QBool custom conversion.
Fix QBool custom conversion.

Reviewed by Marcelo Lira <marcelo.lira@openbossa.org>

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