Fix QSGGeometry object leak

Set QSGNode::OwnsGeometry flag to QSGVideoNode, otherwise the QSGGeometry
object created in QSGVideoNode::setTexturedRectGeometry() will be leaked.

Change-Id: I383b4fe2ff8c7921d2c9c101d4d90fac5a08365a
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>

src/qtmultimediaquicktools/qsgvideonode_p.cpp

@@ -46,6 +46,7 @@ QT_BEGIN_NAMESPACE
 QSGVideoNode::QSGVideoNode()
     : m_orientation(-1)
 {
+    setFlag(QSGNode::OwnsGeometry);
 }
 
 /* Helpers */