Show maas errors

Shows error info from juju machine as well as trying to show unit state-info.
This shows errors that the MAAS api returns when there are no matching nodes for a requested new deploy.
Without this, the unit would always just show as 'pending', when in fact it will never come.

I don't think juju actually ever sets a unit's state to 'error', or ever sets a unit's state-info to anything, but I left that code in in case I missed something.

Also sort the units by name because otherwise they're in dictionary key order which is arbitrary and unstable.

:fish: :fishing_pole_and_fish: :sushi: