[ospfd] Bug #330: SPF must consider that nexthop-calc may fail

[ospfd] Bug #330: SPF must consider that nexthop-calc may fail

2007-01-24 Paul Jakma <paul.jakma@sun.com>

	* ospf_spf.c: Bug #330: Nexthop calculation sometimes may fail,
	  and it needs to indicate this result to SPF.
	  (ospf_spf_add_parent) Flush of parent list needs to be done here,
	  for simplicity.
	  (ospf_nexthop_calculation) Caller needs to know whether
	  nexthop calculation succeeded. Every return statement must
	  correctly indicate such.
	  (ospf_spf_next) Queueing/prioritisation of vertices in SPF
	  must take into account whether nexthop_calculation succeeded,
	  or SPF may fail to find best paths.