tweak cloud setup to try and get rid of anoying noise in check diff

tasks/persistent_cloud.yml

@@ -64,6 +64,7 @@
 - local_action: shell nova --os-auth-url="{{os_auth_url}}" --os-username="admin" --os-password="{{ADMIN_PASS}}" --os-tenant-name={{inventory_tenant}} volume-attach "{{inventory_instance_name}}" "{{item.volume_id}}" "{{item.device}}"
   with_items: "{{volumes}}"
   ignore_errors: True
+  failed_when: False
   when: volumes is defined and volume_available is defined and volume_available
 
 - name: wait for he host to be hot