Add ansible 2.6 repo

images/installer/origin-extra-root/etc/yum.repos.d/centos-ansible26.repo

@@ -0,0 +1,6 @@
+
+[centos-ansible26-testing]
+name=CentOS Ansible 2.6 testing repo
+baseurl=https://cbs.centos.org/repos/configmanagement7-ansible-26-testing/x86_64/os/
+enabled=1
+gpgcheck=0