Comment 4 for bug 1685814

Reopening. The previous fix was only partial, there are still other centos-release-* repos on the images and they're now causing us problems too: http://logs.openstack.org/68/449068/2/gate/gate-tripleo-ci-centos-7-nonha-multinode-oooq/e8a95f8/logs/undercloud/home/jenkins/undercloud_install.log.txt.gz#_2017-05-01_19_09_49