Update cinder usage
Update cinder usage

This patch updates the cinder usage in the overcloud
diskimage-builder command to reflect the recent changes
of splitting the cinder element into cinder, cinder-api
and cinder-volume elements.

Change-Id: I6f3d56c8e754bda3636904c80958b41fc39aa9a5

rdo-management/tripleo,rdo-management/tripleo