Scenario/manager.py: always wait when delete a cinder vol
Scenario/manager.py: always wait when delete a cinder vol

The `wait_on_delete` argument defaulted to True and was never called
with `False`. So remove the complicated call to `addCleanup_with_wait`
to make that explicit.

Change-Id: I8afb089617f82359475a867ae76b8022a58b4af5

Juniper/tempest,bigswitch/tempest,openstack/tempest,masayukig/tempest,Tesora/tesora-tempest,zsoltdudas/lis-tempest,LIS/lis-tempest,masayukig/tempest,cisco-openstack/tempest,vedujoshi/tempest,openstack/tempest,bigswitch/tempest,Tesora/tesora-tempest,sebrandon1/tempest,Juniper/tempest,zsoltdudas/lis-tempest,LIS/lis-tempest,sebrandon1/tempest,cisco-openstack/tempest,vedujoshi/tempest