Open ~/openstack/ardana/ansible/roles/cobbler/templates/sles.grub.j2 with an editor and add self_update=0 to the line starting with linuxefi. The results needs to look like the following:

linuxefi images/{{ sles_profile_name }}-x86_64/linux ifcfg={{ item[0] }}=dhcp install=http://{{ cobbler_server_ip_addr }}:79/cblr/ks_mirror/{{ sles_profile_name }} self_update=0 AutoYaST2=http://{{ cobbler_server_ip_addr }}:79/cblr/svc/op/ks/system/{{ item[1] }}

Commit your changes:

ardana > git commit -m "Disable Yast Self Update feature" \
~/openstack/ardana/ansible/roles/cobbler/templates/sles.grub.j2

If you need to reenable the installer self-update, remove self_update=0 and commit the changes.