As per subject. qnikst said this is a bug, and that rc_cgroup_cleanup is meant to control automatic cgroup cleanup only. That is, a sysadmin should always manually be able to run cgroup_cleanup in the case where they i.e. had to 'zap' a service after it crashed. This fix is particularily important for recent changes in /etc/init.d/xdm for xorg-server-1.14.3-r1, which enables automatic rc_cgroup_cleanup for GDM:3.
This is fixed in commit 993e7d7 and will be included in OpenRC-0.13.
This has also been back ported to OpenRC 0.12.1.