Confconsole - handle removal of default NIC more gracefully

[JedMeister]

Brandon reported on the forums that after removing eth1, Confconsole is crashing with a stacktrace.

As Brandon noted, it seems likely that he had configured eth1 as the default interface, then later removed it.

Whilst removing the default interface may be a legitimate issue, Confconsole should at least handle it more gracefully, with an error message. It'd be even better if it offered the user to change the default interface (assuming one exists), or even automatically resolve it? If the latter is implemented, then it probably should notify the user it's done that?

IIRC we handle the case where there is no interface at all - although I should double check that. Regardless, it obviously isn't handling the case where the default interface is removed.

Regardless, it can be worked around by editing the config file (/etc/confconsole/confconsole.conf) and edit default_nic to 'eth0`. I.e.:

default_nic eth0