hyperv: update hypervObject struct.

hyperv: update hypervObject struct.

Currently named as hypervObjecUnified to keep code
compilable/functional until all bits are in place.

This struct is a result of unserializing WMI request response.
Therefore, it needs to be able to deal with different "versions" of the
same WMI class. To accomplish this, the "data" member was turned in to
a union which:

* has a "common" member that contains only WMI class fields that are
  safe to access and are present in all "versions". This is ensured by
  the code generator that takes care of proper struct memory alignment
  between "common", "v1", "v2" etc members. This memeber is to be used
  by the driver code wherever the API implementation can be shared for
  all supported hyper-v versions.
* the "v1" and "v2" member can be used by the driver code to handle
  version specific cases.

Example:

Msvm_ComputerSystem *vm = NULL;
...
hypervGetVirtualMachineList(priv, wqlQuery, *vm);
...
/* safe for "v1" and "v2" */
char *vmName = vm->data.common->Name;

/* or if one really needs special handling for "v2" */
if (priv->wmiVersion == HYPERV_WMI_VERSION_V2) {
    char *foo = vm->data.v2->SomeV2OnlyField;
}

In other words, driver should not concern itself with existence of "v1"
or "v2" of WMI class unless absolutely necessary.