QTouchEvent::TouchPoint::isPrimary() is gone.

Change-Id: I6fbaac28a060fd527e0226d55419a9055125368a
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>

src/quick/items/qquickcanvas.cpp

@@ -348,7 +348,7 @@ void QQuickCanvasPrivate::translateTouchEvent(QTouchEvent *touchEvent)
         touchPoint.setStartScenePos(touchPoint.startPos());
         touchPoint.setLastScenePos(touchPoint.lastPos());
 
-        if (touchPoint.isPrimary())
+        if (i == 0)
             lastMousePosition = touchPoint.pos().toPoint();
     }
     touchEvent->setTouchPoints(touchPoints);