[bgpd] Handle pcount as flags are changed, fixing pcount issues

[bgpd] Handle pcount as flags are changed, fixing pcount issues

2006-09-06 Paul Jakma <paul.jakma@sun.com>

	* (general) Squash any and all prefix-count issues by
	  abstracting route flag changes, and maintaining count as and
	  when flags are modified (rather than relying on explicit
	  modifications of count being sprinkled in just the right
	  places throughout the code).
	* bgp_route.c: (bgp_pcount_{dec,inc}rement) removed.
	  (bgp_pcount_adjust) new, update prefix count as
	  needed for a given route.
	  (bgp_info_{uns,s}et_flag) set/unset a BGP_INFO route status
	  flag, calling previous function when appropriate.
	  (general) Update all set/unsets of flags to use previous.
	  Remove pcount_{dec,inc}rement calls.
	  No need to unset BGP_INFO_VALID in places where
	  bgp_info_delete is called, it does that anyway.
	* bgp_{damp,nexthop}.c: Update to use bgp_info_{un,}set_flag.
	* bgp_route.h: Export bgp_info_{un,}set_flag.
	  Add a 'meta' BGP_INFO flag, BGP_INFO_UNUSEABLE.
	  Move BGP_INFO_HOLDDOWN macro to here from bgpd.h