In order to satisfy the changes around generic groups in Cinder, the
consistency group calls within the SolidFire driver were wrapped in the
appropriate generic group calls. Asides from a few key changes, there
is no functional change in the underlying methods.
Change-Id: I150133c02f5c35a7ef226f99fe30f34c484c4341
Closes-Bug: #1682241
Implements: blueprint solidfire-add-cg-to-generic-volume-groups
