Pass status option up.

Pass status option up.

If we are in state "renewing" and the DHCPv6 server returns an
unsuccessful status go to "rebinding", i.e. ask any DHCPv6 server for
a lease not just the one we got the lease from.

This likely fixes a problem reported by Brian Conway where the ISP
returned "NoBinding - Prefix not bound to this interface." for a renew.
dhcp6leased recovered once T1 expired and we went to "rebinding" after
some time.