skip invalid video frame in ::paint() of qpaintvideosurface.cpp
skip invalid video frame in ::paint() of qpaintvideosurface.cpp

when video frame is invalid, we should return directly in ::paint()
of qpaintvideosurface.cpp.
otherwise, it will run into branch of QAbstractVideoBuffer::NoHandle,
which will ruin the following ::paint when m_frame.handleType() is not
QAbstractVideoBuffer::NoHandle

Merge-request: 33
Reviewed-by: Dmytro Poplavskiy <72e04cfb587e72184d425a79cb5cea0021f0b982@nokia.com>

KDE/android-qt-mobility,tmcguire/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,enthought/qt-mobility,KDE/android-qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,KDE/android-qt-mobility,tmcguire/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility,enthought/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,kaltsi/qt-mobility,qtproject/qt-mobility,KDE/android-qt-mobility,qtproject/qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,enthought/qt-mobility,qtproject/qt-mobility