Add qos_specs support to solidfire driver

We've added a new qos_specs object to Cinder that allows creation
and management of qos settings separate from volume-types.
Now instead of embedding the qos info in the extra-specs of the
volume-type we associate the desired qos-spec to a volume-type.

This change implements the capability of the SolidFire driver to
take advantage of that feature.

Change-Id: I215bd0cff0c0a91c106de27eea9ec2b91689a46e
Implements: blueprint add-qosspecs-support-to-solidfire-driver
Merge "Add qos_specs support to solidfire driver"