[bgpd] rearrange some structs for less padding, stats for table/attrs.

[bgpd] rearrange some structs for less padding, stats for table/attrs.

2006-03-12 Paul Jakma <paul.jakma@sun.com>

	* bgp_attr.h: (struct attr) rearrange fields to avoid
	  wasted padding between them as much as possible.
	  (attr_count,attr_unknown_count) export new functions to
	  return number of counts of cached attributes.
	* bgp_attr.c: (attr_count,attr_unknown_count) new functions to
	  return number of counts of cached attributes.
	* bgp_route.h: (struct bgp_info) rearrange fields to avoid
	  wasted padding.
	* bgp_table.h: (struct bgp_table) Add a count field, of number
	  of nodes in the table.
	  (struct bgp_node)  rearrange fields to avoid
	  wasted padding between them, though I don't think there
	  was any in this case.
	* bgp_table.c: (bgp_node_{delete,get}) Maintain the table node count.
	  (bgp_table_count) new function to access the table count.