If we are coming from a PPPoE/PPTP WAN type, grab the old physical interface first to avoid assigning a ppp interface to itself. Fixes pppoe->pppoe wizard run as well as changing pppoe->dhcp. Fixes #1696
Related issues
Bug #1696: Panic when finishing setup wizard with PPPoE WAN
If we are coming from a PPPoE/PPTP WAN type, grab the old physical interface first to avoid assigning a ppp interface to itself. Fixes pppoe->pppoe wizard run as well as changing pppoe->dhcp. Fixes #1696