If you replace the membership list of an image with some members
that were previously deleted, we fail to re-add those deleted
members.
This seems to be a consequence of a previous commit
d6800e143d which failed to update
the deleted records.
Closes-Bug: 1527143
Change-Id: Ic3ca9b56712a99652e65cb0a4e3f1e0ba15b8593