Commit beae5647c0 updated the conformance test references to a
deprecated repository. However, by pointing at the docker-hub it
inadvertantly introduce a significant possibility for flakes. This is
because anonymous docker hub access is rate-limited by IP. We cannot
predict the IP used for CI VMs & Containers, any of which could be at or
close to the limit. Fix this by pointing explicitly at a
`quay.io/libpod/centos` repo. which is excluesively for use by CI, with
static images.
Signed-off-by: Chris Evich <cevich@redhat.com>
5a83012c93