Add timestamp checking in AccountBroker.is_status_deleted

Account-reaper works only at account-server with the first replica, and reaps
account with "deleted" status.

On the other hand, account-replicator doesn't replicate the status, only
replicates *_timestamp.
When swift fails to delete the first account replica, account-reaper never
reaps the account, because the first replica never gets marked as "deleted".

This patch adds a timestamp checking into is_status_deleted method, and
account-reaper will start to reap the account after account-replicator
replicates *_timestamp.

Change-Id: I75e3f15ad217a71b4fd39552cf6db2957597efca
Closes-Bug: #1304755
Merge "Add timestamp checking in AccountBroker.is_status_deleted"