libcontainer: use inactive_file on cgroup v2
libcontainer: use inactive_file on cgroup v2

total_inactive_file is present only on cgroup v1

Signed-off-by: Giuseppe Scrivano <20002b7b24c75512093a71a58285826d5c504fca@redhat.com>

linux-on-ibm-z/cadvisor,linux-on-ibm-z/cadvisor,linux-on-ibm-z/cadvisor