Editor - Fix ObjectPropertyEntryBox to once again work without a PropertyHandle
Backed out part of changelist 2320455 to get the Asset Override Editor selection boxes working again.
#codereview Richard.TalbotWatkin
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Integrated using branch Ue4-To-UE4-Fortnite-Simple (reversed) of change#2325726 by Jaren.Peterson on 2014/10/10 13:29:25.
[CL 2325858 by Jaren Peterson in Main branch]