Fix compile error

Change-Id: Iba3860ef8ea940b8f232e21e273b0ac83d895882
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Fix copying of Property's

Data properties don't contain valid data in the set field
if they are being stored in Objects. Thus we should never
access that field unless we are dealing with accessor
properties.

Change-Id: I19dcbaee7ebd042ae24387f92a93571d75ca578a
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>