Update "Install via Kolla Ansible" docs for CentOS 8.
Change-Id: If13d126046eb12b330ab7d45808c82aee3e37305
(cherry picked from commit c48560c31d)
Update "Install via Kolla Ansible" docs for CentOS 8.
Change-Id: If13d126046eb12b330ab7d45808c82aee3e37305
(cherry picked from commit c48560c31d)