[Libvirt-cim] [PATCH 0 of 3] Add call to libvirt to create storage volume

This set also has creates a StorageVolume instance to return to the user. Ideally, the bit of code in patch 3 should be in Virt_RASD, but that takes some signigicant amount of reshuffiling in the Virt_RASD provider. This will be fixed after this set of patches goes in. This is the last set of patches to get basic image creation working.