Change default CgroupMountpoint (in cgroup.release example)

Introduced in c97e08a0
Change default CgroupMountpoint (in cgroup.conf) from "/cgroup" to
    "/sys/fs/cgroup" to match current standard.
For details, see https://wiki.freedesktop.org/www/Software/systemd/PaxControlGroups/

etc/cgroup.release_common.example.in

@@ -24,7 +24,7 @@ get_mount_dir()
     elif X=$(grep -si -m1 "^CgroupMountpoint=" @sysconfdir@/cgroup.conf); then
         echo $X | sed "s/.*=\(.*\)/\1\/${subsystem}/"
     else
-        echo "/cgroup/$subsystem"
+        echo "/sys/fs/cgroup/$subsystem"
     fi
 }