Better --check compatibility for ceph-common 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-common/tasks/main.yml

@@ -169,12 +169,14 @@
   shell: "stat /var/run/ceph/*.asok > /dev/null 2>&1"
   changed_when: false
   failed_when: false
+  always_run: true
   register: socket
 
 - name: check for a rados gateway socket
   shell: "stat {{ rbd_client_admin_socket_path }}*.asok > /dev/null 2>&1"
   changed_when: false
   failed_when: false
+  always_run: true
   register: socketrgw
 
 - name: create a local fetch directory if it does not exist
@@ -197,6 +199,7 @@
   changed_when: false
   register: cluster_uuid
   become: false
+  always_run: true
   when: generate_fsid
 
 - name: create ceph conf directory