do not reset rcvif for icmp6_error().  it's meaningless, since icmp6_error() and _reflect() ignore the value.
do not reset rcvif for icmp6_error().  it's meaningless, since icmp6_error()
and _reflect() ignore the value.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame