Fix regression in QListView

The fix was originally applied to Qt 4.8 (4c64464), but missed
Qt 5 which had already been branched at that point of time.

Task-number: QTBUG-33089
Task-number: QTBUG-21433
Change-Id: Ia3cd35d29dbdc70ba55b6f0840c4082e232c24ae
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>