Rename Cinder role

The name and the description of the storage role in openstack.yaml
was hardcoded to mention that this role provides block storage over
iSCSI and uses LVM. That is not true for cases when VMware vCenter
is used as a back-end for storage.

This patch changes those name and description to more common ones.
After this is merged it's required to update screenshotsi, referencesand
descriptions in at least the followind docs:

 * User guide
 * Reference Architectures
 * Fuel developer's documentation

DocImpact
Closes-bug: 1383224
Change-Id: I4aa013611242ff6b7e6e0889b38bfbf9e9a700ec
Merge "Rename Cinder role"