Add response schema validation for volume qos-specs

This is to add response schema validation for volume
qos-specs.
Besides, there are some inconsistencies in volume qos-specs api ref,
Ib5c9b3a15ee2ca40c19e7a530d1ff5351d3dcaf8 will fix them.

Change-Id: I433c78821185600a230803cddec54a5d264c2ca5
partially-implements: blueprint volume-response-schema-validation
2 files changed