[bgpd] Document the FSM dummy-peer race that sometimes afflicts session setup

* bgp_packet.c: (bgp_open_receive) the accept-peer hack can sometimes
  cause a race between two peers that try to establish sessions to each other,
  causing session setup to fail when it should have succeeded. In the worst
  case, the race can 'loop', causing prolonged failure to establish sessions.
1 file changed