Hello,

I am using propellor mostly with Systemd containers. I have a problem when
trying to use `Ssh.knownHost`, as the host to be known is not a host, but a
container.

Is this supposed to work? Are containers accessible like the other hosts with
the info system?

Also, I used short names for my containers, like:

    vzWeb2 :: Systemd.Container
    vzWeb2 = Systemd.debContainer "vz-web2" $ props

but now I realize that I should have used a fqdn so that properties like
`Hostname.sane` could find the domain name. But changing this implies that the
container will be rebuilt, right?
