Add RHEL distro available for building images
Add RHEL distro available for building images

Change-Id: I8a113f98f4a916ab91de45029a2390d06ae4ea65
Signed-off-by: Taeha Kim <8a2186a2c0677c135aac25a2f2eb39c04ed802ad@gmail.com>

stackforge/kolla,mrangana/kolla,stackforge/kolla,rahulunair/kolla,stackforge/kolla,rahulunair/kolla,openstack/kolla,nihilifer/kolla,mrangana/kolla,nihilifer/kolla,openstack/kolla