Currently, the expirer daemon treats 412 (precondition failed)
as successful DELETEs.
On the other hand, it treats 404 as failed while reclaim_age
(usually a week) has not passed.
This patch unifies both cases to the same handling: waiting for
reclaim_age to pass, then deleting the entry.
The reason the expirer should not delete a 412 entry right away,
is that it might be the case that 412 is returned because of
a split brain, where the updated object servers are currently down.
Same reason holds for a 404 response.
Change-Id: Icabbdd72746a211b68f266a49231881f0f4ace94
4aa1ae61cb