systemd: fix smack error

systemd: fix smack error

A user systemd session accesses /proc/1/sched to detect container.

Jan 01 09:00:14 localhost audit[636]: AVC lsm=SMACK fn=smack_inode_permission action=denied subject="User" object="System::Privileged" requested=r pid=636 comm="systemd" name="sched" dev="proc" ino=12247
Jan 01 09:00:14 localhost audit[636]: AVC lsm=SMACK fn=smack_inode_permission action=denied subject="User" object="System::Privileged" requested=r pid=636 comm="systemd" name="sched" dev="proc" ino=12247
Jan 01 09:00:14 localhost audit[636]: AVC lsm=SMACK fn=smack_inode_permission action=denied subject="User" object="System::Privileged" requested=r pid=636 comm="systemd" name="sched" dev="proc" ino=12247
Jan 01 09:00:23 localhost audit[915]: AVC lsm=SMACK fn=smack_inode_permission action=denied subject="User" object="System::Privileged" requested=r pid=915 comm="systemctl" name="sched" dev="proc" ino=12247

Change-Id: I0d6f632b090582888c45f309c8a8bf06f4f0f510