fix QtXml to build without warnings
fix QtXml to build without warnings

please ignore the remark of the last check-in. QtXml should have been corrected before the defendant QtUiTools

gbaty/pyside2,BadSingleton/pyside2,IronManMark20/pyside2,IronManMark20/pyside2,qtproject/pyside-pyside,qtproject/pyside-pyside,IronManMark20/pyside2,gbaty/pyside2,gbaty/pyside2,BadSingleton/pyside2,IronManMark20/pyside2,BadSingleton/pyside2,qtproject/pyside-pyside,BadSingleton/pyside2,gbaty/pyside2,gbaty/pyside2,qtproject/pyside-pyside,qtproject/pyside-pyside,BadSingleton/pyside2,IronManMark20/pyside2