Add a retry_on_deadlock to reservations_expire

Now that we have an index for the reservations_expire query, we
have uncovered a race with quota usage updates due to the foreign
key on the table, so just retry if there is a deadlock. This is
a fix to unblock the gate while we try to remove the deadlocks
completely.

Change-Id: I1993c3bd1f81facf1d98a4e29f9e8df4858a7d66
Partial-bug: #1350466