Code review comment for lp:~hopem/charm-helpers/allow-list-nics-return-all

Please could you update the unit tests so that the macs of IP_LINE_ETH0 and IP_LINE_ETH0_VLAN match and add a test for list_nics(['eth'], include_vlans=False) ?

As a nitpick I think it's cleaner parse the output of ip when using '-o' so that all entries are on one line but that's how it was before so I won't block on it.