disk_images:
  -
    imagename: overcloud-hardened-uefi-full
    type: qcow2
    distro: centos
    environment:
      DIB_RELEASE: '8'
    elements:
      - selinux-permissive
      - interface-names

Add missing image yaml for centos 8
Add missing image yaml for centos 8

Change-Id: Ib4607d1d9e7372582f19f26a22025de973813cf9
