Remove volume v1 API service client usage

Volume v1 API has been gone since long and Tempest also
marked their deprecation since Juno
- https://review.openstack.org/#/c/446238/

Now Tempest is removing the deprecated config option and
alias for voluem v1 service client in
- https://review.openstack.org/#/c/573135/

Before the Tempest patch gets merged, we need to remove all usage
of volume v1 things.

Change-Id: Iac5d1914814afbe81f3d83c875620931884584cd
Needed-By: https://review.openstack.org/#/c/573135/
1 file changed