[Libvirt-cim] [PATCH 0 of 4] Add clock offset support

This patch set adds the ability to control the clock offset of a guest from the CIM providers, which is important with dealing with Windows guests. It gives us: - The ability to specify the offset during DefineSystem - The ability to inspect the offset in the VSSD object - The knowledge of the <clock> element in libvirt XML so as not to clobber it when adjusting the XML as part of another action