update ip_len to reflect tunnel header removal (lost duing ip_len flip changes); ok itojun; noticed by jrrs@ice-nine.org
update ip_len to reflect tunnel header removal (lost duing ip_len
flip changes); ok itojun; noticed by jrrs@ice-nine.org

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars