[bgpd] Fix peer prefix counts and make it slightly more robust

[bgpd] Fix peer prefix counts and make it slightly more robust

2006-02-05 Paul Jakma <paul.jakma@sun.com>

	* bgp_route.h: Add BGP_INFO_COUNTED to track whether
	  prefix has been counted or not.
	* bgp_route.c: (bgp_pcount_{inc,dec}rement) new helpers, to
	  centralise inc/dec of prefix-count,
	  (bgp_rib_remove) Remove pcount decrement, use helper.
	  (bgp_rib_withdraw) ditto, additionally use previous function
	  too.
	  (bgp_update_main) Use pcount helpers.
	  (bgp_clear_route_node) ditto, aslo REMOVED routes don't need
	  clearing.