Fix for undefine variable
Fix for undefine variable

If the template boolean ceph_standalone wasn't defined
the playbook would fail. Define the variable with a default value
so it never fails.

Change-Id: Id83337a29bdd6f4b7493536e78fa29167d2fe82e

open-power-ref-design-toolkit/opsmgr,open-power-ref-design/opsmgr,open-power-ref-design-toolkit/opsmgr,open-power-ref-design/opsmgr,open-power-ref-design/opsmgr,open-power-ref-design-toolkit/opsmgr,open-power-ref-design-toolkit/opsmgr,open-power-ref-design/opsmgr,open-power-ref-design-toolkit/opsmgr,open-power-ref-design/opsmgr