Better --check compatibility for ceph-mon role

Carefully chosen "always_run: true" parameters for read-only tasks that
register variables. This enables --check runs (at least on deployed
clusters).

roles/ceph-mon/tasks/ceph_keys.yml

@@ -25,6 +25,7 @@
   shell: ls -1 /etc/ceph/*.keyring
   changed_when: false
   register: ceph_keys
+  always_run: true
   when: cephx
 
 - name: set keys permissions

roles/ceph-mon/tasks/deploy_monitors.yml

@@ -12,6 +12,7 @@
   changed_when: false
   register: monitor_keyring
   become: false
+  always_run: true
   when: cephx
 
 - set_fact: