tests: run switch_to_containers against nautilus
tests: run switch_to_containers against nautilus

even on master, force the release to be nautilus.
this scenarios is failing because at multiple times this scenario is
actually downgrading the ceph version.
It might happen that the latest-master image is older than what was
deployed in the first step of the scenario (the RPM deployment).

Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>
(cherry picked from commit 41b0fa15ddf2a45402d17faa3bd1e817692fc1d2)

ceph/ceph-ansible,ceph/ceph-ansible