Fixed QML Item updates after reparenting.
Fixed QML Item updates after reparenting.

Setting an Item's parent to null caused its scene graph nodes to
be deleted, but resetting the parent to a valid object did not
recreate and update all the nodes.

Task-number: QTBUG-21032
Change-Id: I00f93a481a326ba9b9fb98bf4212479622552783
Reviewed-by: Gunnar Sletta <d0b71651f3efaa9fda200bbcc395b7b82a871fdd@nokia.com>

matthewvogt/qtdeclarative,jfaust/qtdeclarative,corngood/qtdeclarative,matthewvogt/qtdeclarative,jfaust/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,crobertd/qtdeclarative,corngood/qtdeclarative,crobertd/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,crobertd/qtdeclarative,crobertd/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,crobertd/qtdeclarative,corngood/qtdeclarative,matthewvogt/qtdeclarative,jfaust/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,jfaust/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,crobertd/qtdeclarative,crobertd/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,corngood/qtdeclarative,qmlc/qtdeclarative,corngood/qtdeclarative,corngood/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,jfaust/qtdeclarative,jfaust/qtdeclarative,corngood/qtdeclarative,jfaust/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative