[ospfd] cleanup NSM neighbour delete through a new Deleted NSM state

[ospfd] cleanup NSM neighbour delete through a new Deleted NSM state

2006-07-07 Paul Jakma <paul.jakma@sun.com>

	* ospf_nsm.h: Add a NSM_Deleted neighbour state, to act as dummy
	  state indicating the neighbour is to be deleted.
	* ospf_nsm.c: (general) Use the NSM_Deleted state to delete
	  neighbours, thus allowing code to be slightly more obvious
	  in its flow.
	  (nsm_timer_set) Add NSM_Deleted. Add another timer the code
	  missed.
	  (nsm_kill_nbr) No need for special case call to nsm_change_state
	  anymore.
	  Make the assert and error-handling for same case more readable
	  (Andrew Schorr)
	  Remove the call to ospf_nbr_delete, nsm_change_state can do
	  this generally now via NSM_Deleted.
	  (struct ... NSM) Add the dummy NSM_Deleted state, the 3 events
	  that can lead to nsm_kill_nbr all now transition the NBR to
	  NSM_Deleted and the general change_state function can be left
	  to do the work.
	  (ospf_nsm_event) Special casing of events and early-return can
	  be removed now.
	  On transition into Deleted, delete the nbr.
	* ospf_dump.c: (ospf_nsm_state_msg) Add Deleted.