Revert "lxc: controller: Fix container launch on cgroup v1"

Revert "lxc: controller: Fix container launch on cgroup v1"

Unfortunately, this fix breakes machinectl in a very nasty way,
for instance 'machinectl shell' drops into the host shell. It's
worse than being unable to start a container with CGroupsV1.

Revert until a proper fix is figured out.

This reverts commit 1b9ce05ce241a581d4e80228c92ceb0266f21f94.

References: https://gitlab.com/libvirt/libvirt/-/issues/182
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>