Fix building signalmanager.cpp with Qt 5.4.x.
Fix building signalmanager.cpp with Qt 5.4.x.

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