Fix 'tempest cleanup' for volume service client

In below patch, volume service clients alias in cleint.py
has been changed and out under version checks condition.
- I1400a870de483f5cdf125eae2a9be68b46b54343

But tempest cleanup cmd used the alias not present for all
version and get no attribute error if volume v2 or v3 version
is configured.

Change-Id: I1d0d86417ce6d92bfa0ef450ceb70dd480978fe1
Closes-Bug: #1727569
1 file changed