QML objects are fetched lazily when constructing the object tree.
Incase parents have not been previously fetched, we fetch the
required data to construct only the relevant branch of the tree.

Task-number: QTCREATORBUG-8246
Change-Id: Id529c3b2334d33ff4eb46b14f50cf042ad2960e2
Reviewed-by: hjk <qthjk@ovi.com>