bgpd: On shutdown do not create a workqueue for the self peer

bgpd: On shutdown do not create a workqueue for the self peer

When bgp is shutting down, it calls bgp_fsm_change_status
on everything including a self peer, which goes through
and cleans the tables of the self peer data structures
as if it's a real peer.  Add a bit of code to just
not do the work at all.  This allows unlocks to flow
a bit further and for the self peer to be deleted
on shutdown.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>