Sharing codes for volumes list tests

1. merge the common tests between v1 and v2, and set its
   default value for v2.
2. make volumes v1 list tests inherits common tests
3. leave volumes v2 specific tests in direcotry 'tempest/api/volume/v2'
4. delete BaseVolumeV2Test

Partially implements: blueprint cinder-v2-api-tests

Change-Id: I7cecbde9543c441a2f3478941f85625755aabf7f
Merge "Sharing codes for volumes list tests"