osds: wait for osds to be up before creating pools

osds: wait for osds to be up before creating pools

This is a follow up on #2628.
Even with the openstack pools creation moved later in the playbook,
there is still an issue because OSDs are not all UP when trying to
create pools.

Adding a task which checks for all OSDs to be UP with a `retries/until`
condition should definitively fix this issue.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1578086
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>