osd: do not release recovery_ops_reserved on requeue

osd: do not release recovery_ops_reserved on requeue

This doesn't make sense.. although it's the same behavior as
luminous.

The point of the releases here is that if we drop something that is in
the queue we drop the recovery_ops_reserved counter by that much.  However,
if something is in the queue and waiting, and we wake it back up, there
is no net change to _reserved... which is only decremented when we
actually dequeue something.

Signed-off-by: Sage Weil <sage@redhat.com>