- do not SEGV on IFF_UP. - recover rrt_gw setting for non-p2p case.  otherwise, we will not   be able to recover interface route on interface down -> up   transition. - clarify loop exit condition
- do not SEGV on IFF_UP.
- recover rrt_gw setting for non-p2p case.  otherwise, we will not
  be able to recover interface route on interface down -> up
  transition.
- clarify loop exit condition

Obtained from:	KAME
MFC after:	1 week

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