[bgpd] Fix bug where a deleted route that was quickly re-added was being lost

[bgpd] Fix bug where a deleted route that was quickly re-added was being lost

2006-11-28 Andrew J. Schorr <ajschorr@alumni.princeton.edu>

	* bgp_route.c: (bgp_info_restore) New function that undoes
	  the effects of a previous call to bgp_info_delete.  This is
	  used when a route is deleted and quickly re-added before the
	  deletion has been processed.
	  (bgp_static_update_rsclient, bgp_static_update_main,
	  bgp_redistribute_add) Check whether a pre-existing route
	  has the BGP_INFO_REMOVED set, and, if so, we need to call
	  bgp_info_restore to resurrect it.