Fixes a Hyper-V list_instances localization issue

The Hyper-V WMI MSVM_ComputerSystem class Caption property can
have different values on various locales. This patch uses a
different query to avoid any localization issue.

Co-Authored-By: Robert Tingirica <rtingirica@cloudbasesolutions.com>
Change-Id: I15103b8edb3ff8934c835826ed00e08593cdeacc
Closes-Bug: #1296478
Merge "Fixes a Hyper-V list_instances localization issue"