tests: avoid yum failures

tests: avoid yum failures

In the CI we can see at many times failures like following:

`Failure talking to yum: Cannot find a valid baseurl for repo:
base/7/x86_64`

It seems the fastest mirror detection is sometimes counterproductive and
leads yum to fail.

This fix has been added in the `setup.yml`.
This playbook was used until now only just before playing `testinfra`
and could be used before running ceph-ansible so we can add some
provisionning tasks.

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
Co-authored-by: Erwan Velu <evelu@redhat.com>