Fixed a kernel crash due to a duplicated free when net.inet[6].ip[6].rtexpire=0.
(this bug is specific to FreeBSD-4.x, so it's not committed to -CURRENT nor RELENG-5)
Reported in: freebsd-net ("Weird memory exhaustion with FreeBSD 4.10-STABLE" starting from Sep 23, 2004)
Obtained from: KAME
Approved by: re (scottl)