smoktest: interface: disable base mirror test
smoktest: interface: disable base mirror test

One should not use hardcoded interfaces in this base class, rather rely on
self._options like every other test. This implementation breaks on my development
system ans also deletes my OSPF dummy mgmt interface :(.

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