Fix crash on shutdown with states

When populating deferred properties, we must not set the rootObjectInCreation
flags on the root context and (consequently) on any sub-objects objects created
when initializing deferred properties. Doing so otherwise will end up us
incorrectly linking QQmlContextData together, causing QQmlData::linkedContext
to point to iself and crash on exit upon deletion.

Task-number: QTBUG-37484
Change-Id: Ia5dc92a04e0f66499f15fbac10f14859d387b021
Reviewed-by: Lars Knoll <lars.knoll@digia.com>