cinder v2 api tests - part1

Change volume base class name:
BaseVolumeTest -> BaseVolumeV1Test
BaseVolumeAdminTest -> BaseVolumeV1AdminTest
for the support of cinder V2 test class

Implements: blueprint cinder-v2-api-tests

Change-Id: I712a90d39981564af09393ed1b7f4be12897c808
Merge "cinder v2 api tests - part1"