Since PyMI requires the MI API, available only since Windows 8 /
Windows Server 2012 or as an addon on some previous versions, we
need to ensure that we fall back to the legacy WMI module if PyMI
cannot be loaded.
Partially-Implements: blueprint json-network-config
Change-Id: Ibded4cee3d3d7dc39e53bca12e015c9ef83c7f3d