gitlab-runsvdir cannot be enabled on RHEL6

It's not possible to enable the gitlab-runsvdir service on RHEL 7

[root@centos-66-x64 gitlab]# /sbin/chkconfig --add gitlab-runsvdir
service gitlab-runsvdir does not support chkconfig

So the service will not be running on boot.

This works fine on RHEL7, as the systemd script allows it:

[root@centos-7-x64 vagrant]# /bin/systemctl enable gitlab-runsvdir
[root@centos-7-x64 vagrant]# /bin/systemctl is-active gitlab-runsvdir
active

From my understanding of init scripts, only this needs to be added:

# chkconfig: 345 99 01
# description: gitlab-runsvdir

for it to work. I'll see if I can make a merge request.