Removed storage configuration from nova.conf when doing unconfigure

Issue: unconfigure of livem didnt remove the storage_scope from
nova.conf. This caused local VMs spawn to fail.
Fix: Removed the storage_scope from nova.conf during unconfigure
Closes-Bug: #1366669

Change-Id: Ie9699b4cb6423dba5e1c0e9eede9d87179c7cbf1