if we are running in a container in the root cgroup, Podman tries to
move itself to a sub-cgroup. This could be a problem in a setup where
the cgroups are not writeable, so just log a debug message and
continue, since anyway it is a best-effort operation.
Closes: https://github.com/containers/podman/issues/15498
[NO NEW TESTS NEEDED]
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>