OpenVPN interface doesn't get added to bridge after reboot
When using an interface assigned to an OpenVPN tap interface in a bridge, it won't be added correctly after rebooting. Probably it tries to add the interface before OpenVPN has started up. After booting and re-assigning the bridge interfaces, it works as expected until next reboot.
Fixes #1666. Check if the interface needs to be added to a bridge during rc.newwanip as well.