QA: Cluster-verify reports shared PVs with exclusive storage

Exclusive storage forbids sharing PVs between unrelated LVs. This is a test
that cluster-verify correctly report such cases.

Signed-off-by: Bernardo Dal Seno <bdalseno@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>