defaults: remove `run_once: true` when creating fetch_directory

because of `serial: 1`, it can be an issue when the playbook is being
run on client nodes.
Since the refact of `ceph-client` we skip the role `ceph-defaults` on
every node except the first client node, it means that the task is not
going to be played because of `run_once: true`.

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>

roles/ceph-defaults/tasks/facts.yml

@@ -66,7 +66,6 @@
     state: directory
   changed_when: false
   become: false
-  run_once: true
   when:
     - (cephx or generate_fsid)