[bgpd] Bug #533: Fix crash with copy/pasted commands, inc 'no bgp ...'

* bgpd.c: Removal of (struct bgp *) from the master list was being left to
  bgp_free time.  This meant there was a window of time between bgp_delete
  and refcounts hitting 0 (e.g.  routes to be processed) where bgp_lookup's
  could return a deleted (struct bgp *).

  (bgp_delete) This is the logical place where a (struct bgp *) should lose
  its visibility, so move the deletion from the bgp-master list to here,
  from bgp_free.

  Many thanks to Fritz Reichmann for his thorough debugging of the problem
  and testing of fixes and Chris Caputo for his further analysis.
1 file changed