mwan3 2.0-3 completely broken with tun ifaces

[KyleSanderson]

Currently trying to get 2.0-3 to function properly in LEDE. Trying the various tips suggested in the past such as setting the default gw, remove tracking IPs, etc. mwan3 insists tun0 is down because ubus returns nothing for tun... Copied my exact config from OpenWRT Chaos Calmer, from where the exact same /etc/config/openvpn, /etc/config/network, and /etc/config/mwan3 worked, to find it not working against the rewrite.

@etomm covered the issue quite well in openwrt/packages#3486 (found it after I found the same problem...) which seems to have been largely ignored. Any feedback would be appreciated @Adze1502 .

[KyleSanderson]

openwrt/packages#3110

Exact same issue with another platform.