Fix QQmlDelegateModel ignoring layoutChange in certain situations

Fix a regression introduced by commit a0aefe1 which caused the model to
ignore layout changes if d->m_adaptorModel.rootIndex was just a descendant
of any of the parent indexes, or when no parent indexes at all were provided
in the notification.

Task-number: QTBUG-39492
Change-Id: I4c97929d25ef75947ccfcbbe5bc234096689c58d
Reviewed-by: Alan Alpert <aalpert@blackberry.com>
Delete objects created by qmlplugindump

This helps plugin objects to shut down cleanly

Change-Id: I167f63220a35a7428f50715a4cb9072320ef1c87
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>
Merge remote-tracking branch 'origin/stable' into 5.3

Conflicts:
	tests/auto/quick/qquicklistview/tst_qquicklistview.cpp

Change-Id: I80584b4f7d62cd86d3449e19176118e3bed886c1