Revert "vars: redhat-7: Prefer the cloud repository over the EPEL one"
Revert "vars: redhat-7: Prefer the cloud repository over the EPEL one"

According to [1] the repo with the lowest number has the highest
priority, and therefore it was originally correct. This change has now
set epel to a higher priority which is breaking deployments.

This reverts commit 7f073403098f13a0809c0ccc4dcdca9dd4579104.

[1] https://wiki.centos.org/PackageManagement/Yum/Priorities

Change-Id: Iea469506eb5d6a7c4118a0d441b0bf6aa8b6514b

openstack/openstack-ansible-openstack_hosts,openstack/openstack-ansible-openstack_hosts