Enable EPEL for openstack-ansible CentOS bindeps packages

https://review.openstack.org/#/c/459462/ fixed the Ubuntu check
job but the CentOS job fails at the bindep builder because
python-ndg_httpsclient is not available in the base CentOS repos.

This is based on the OSA job implementation [1].

[1]: 240c1e9696/jenkins/jobs/ansible-role-jobs.yaml (L66-L116)

Change-Id: Ia7e971379c9004eb2911697f6a4e272864ebd66a

jenkins/jobs/ara.yaml

@@ -63,7 +63,21 @@
       - print-template-name:
           template-name: "{template-name}"
       - openstack-ansible-tests-checkout
+      - shell: |
+          if [[ "{name}" == *"openstack-ansible"* ]]; then
+            # EPEL must be enabled because some deps from bindep.txt are
+            # otherwise not available
+            if [[ -e /usr/bin/yum ]]; then
+              sudo yum-config-manager --enable epel
+            fi
+          fi
       - install-distro-packages
+      - shell: |
+          if [[ "{name}" == *"openstack-ansible"* ]]; then
+            if [[ -e /usr/bin/yum ]]; then
+              sudo yum-config-manager --disable epel
+            fi
+          fi
       - shell: |
           # Allow Jenkins user to ssh into localhost
           ssh-keygen -f ~/.ssh/id_rsa -N ""