sh/rc-cgroup.sh: add openrc. prefix the cgroupv2 path

Some services, like docker, creates and manages /sys/fs/cgroup/<service>
themselves. Avoid conflict with the openrc created cgroup path by adding
a `openrc.` prefix.

Fixes: #680

sh/rc-cgroup.sh

@@ -191,7 +191,7 @@ cgroup2_set_limits()
 	cgroup_path="$(cgroup2_find_path)"
 	[ -z "${cgroup_path}" ] && return 0
 	mountinfo -q "${cgroup_path}"|| return 0
-	rc_cgroup_path="${cgroup_path}/${RC_SVCNAME}"
+	rc_cgroup_path="${cgroup_path}/openrc.${RC_SVCNAME}"
 	[ ! -d "${rc_cgroup_path}" ] && mkdir "${rc_cgroup_path}"
 	[ -f "${rc_cgroup_path}"/cgroup.procs ] &&
 		printf 0 > "${rc_cgroup_path}"/cgroup.procs