validate: force ansible version
validate: force ansible version

We currently only support Ansible 2.4.X so let's fail if the version is
different.

Signed-off-by: Sébastien Han <62d754cc350e84d3b1c32ae79f976f5348e74a40@redhat.com>

font/ceph-ansible,ceph/ceph-ansible,ceph/ceph-ansible,font/ceph-ansible,fgal/ceph-ansible,fgal/ceph-ansible