Clean up the calls to group_add_service

This function should only be called once and it does not take any
arguments.

X-Gentoo-Bug: 639166
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=639166

sh/openrc-run.sh.in

@@ -264,8 +264,7 @@ for _cmd; do
 				eerror "No permission to apply cgroup settings"
 				break
 			fi
-			cgroup_add_service /sys/fs/cgroup/openrc
-			cgroup_add_service /sys/fs/cgroup/systemd/system
+			cgroup_add_service
 		fi
 		[ "$(command -v cgroup_set_limits)" = "cgroup_set_limits" ] &&
 			cgroup_set_limits