Allow kwargs in create_volume_type

As a part of the scenario/manager.py stabilization tracked by
the below BP the patch adds kwargs argument for create_volume_type
method so that the consumers are able to pass additional parameters
if needed.

Implements: blueprint tempest-scenario-manager-stable
Change-Id: I4d8236f4b2222c6a07aaafc502c3b660d49d663c
1 file changed