rolling_update: create rbd and rbd-mirror keyrings

rolling_update: create rbd and rbd-mirror keyrings

During an upgrade ceph won't create keys that were not existing on the
previous version. So after the upgrade of let's Jewel to Luminous, once
all the monitors have the new version they should get or create the
keys. It's ok to have the task fails, especially for the rbd-mirror
key, which only appears in Nautilus.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1650572
Signed-off-by: Sébastien Han <seb@redhat.com>
(cherry picked from commit 4e267bee4f9263b9ac3b5649f1e3cf3cbaf12d10)