When we moved to the new Namespace types in Specgen, we made a
distinction between taking a namespace from a pod, and taking it
from another container. Due to this new distinction, some code
that previously worked for both `--pod=$ID` and
`--uts=container:$ID` has accidentally become conditional on only
the latter case. This happened for Hostname - we weren't properly
setting it in cases where the container joined a pod.
Fortunately, this is an easy fix once we know to check the
condition.
Also, ensure that `podman pod inspect` actually prints hostname.
Fixes#6494
Signed-off-by: Matthew Heon <matthew.heon@pm.me>