Fix regression in ScrollView

The regression was introduced in
060a6afd



The parent of our contentItem should really be the
flickables contentItem. Otherwise we don't scroll at all.

Change-Id: I75a9b68134bb2098f59436d23ff79ec600321963
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

src/controls/ScrollView.qml

@@ -146,7 +146,7 @@ FocusScope {
             internal.flickableItem = contentItem // "Use content if it is a flickable
         } else {
             internal.flickableItem = flickableComponent.createObject(this)
-            contentItem.parent = internal.flickableItem
+            contentItem.parent = internal.flickableItem.contentItem
         }
         internal.flickableItem.parent = viewportItem
         internal.flickableItem.anchors.fill = viewportItem