Fix wrong example of "nova_endpoint_template"

In cinder.conf

e.g. http://localhost:8774/v2/%(tenant_id)s

should be

e.g. http://localhost:8774/v2/%(project_id)s

Change-Id: I7dd3be9bc9d2e8f26619b00b5bdbc66505a984b2
Closes-Bug: #1279747
Merge "Fix wrong example of "nova_endpoint_template""