op-mode: T2731: fix "show interfaces" returns invalid state when link is down
op-mode: T2731: fix "show interfaces" returns invalid state when link is down

There has been a miss-match of admin-down and oper-down status for the Python
implementation of "show interfaces".

vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x