add volume list tests for cinder v2

cinder v2 allows parameters limit, sort_key and sort_dir in query
statement. Add tests for the query parameters.

Change-Id: I3b713f3d830879b4e8e675910366c21953e342db
Blueprint: cinder-v2-api-tests
Stop heat resource leaking even if an error occurs

In some test, if an error occurred in setUpClass(), some resources
are not deleted because of tearDownClass() is not called.
This commit fixes it.

 tempest/api
  +---- baremetal (unnecessary)
  +---- compute
  +---- data_processing (unnecessary)
  +---- database (unnecessary)
  +---- identity
  +---- image (done)
  +---- network
  +---- object_storage
  +---- orchestration         <-- this patch
  +---- queuing (unnecessary)
  +---- telemetry (unnecessary)
  +---- volume (done)

Partially Implements: blueprint stop-leaking

Change-Id: Ice13507f4b7625b73fe200c414fa4d7b9be856d5
Merge "Stop heat resource leaking even if an error occurs"
Merge "add volume list tests for cinder v2"