Use openshift testing repos for openstack

Use testing openshift repos to sidestep packaging issues for 3.6 clients being
used in 3.7 deployments or something.
Poke host requirements Centos 7.4 as 7.3 can't see that testing repo.

Signed-off-by: Bogdan Dobrelya <bdobreli@redhat.com>

playbooks/openstack/README.md

@@ -24,7 +24,7 @@ The OpenStack release must be Newton (for Red Hat OpenStack this is
 version 10) or newer. It must also satisfy these requirements:
 
 * Heat (Orchestration) must be available
-* The deployment image (CentOS 7 or RHEL 7) must be loaded
+* The deployment image (CentOS 7.4 or RHEL 7) must be loaded
 * The deployment flavor must be available to your user
   - `m1.medium` / 4GB RAM + 40GB disk should be enough for testing
   - look at

playbooks/openstack/sample-inventory/group_vars/OSEv3.yml

@@ -1,5 +1,6 @@
 ---
 openshift_deployment_type: origin
+openshift_repos_enable_testing: true
 #openshift_deployment_type: openshift-enterprise
 #openshift_release: v3.5
 openshift_master_default_subdomain: "apps.{{ openshift_openstack_clusterid }}.{{ openshift_openstack_public_dns_domain }}"