The API on IHardDiskAttachment is merged into IMediumAttachment.
So, we don't need it anymore.

The GetMedium will always return a IHardDisk object them.
In 2.2 and 3.0, it is what GetHardDisk exactly do. In 3.1 and later,
The IMedium is same as IHardDisk.

If the <path> in target element is not given, libvirt will put the
new volume in ~/.VirtualBox by default.

The CreateHardDiskMedium only support create HardDisk for medium
type, and it only works when vbox version >= 3.1. This patch make
the function workable with all vbox versions and rename it as
CreateHardDisk.

In vbox 2.2 and 3.0 this function will create a IHardDisk object.
In vbox later than 3.0, this function will create a IMedium object.

In old version, function FindMedium in UIVirtualBox doesn't work
for vbox2.2 and 3.0. We assume it will not be used when vbox in
these versions.

But when rewriting vboxStorageVolLookupByPath, we found it was
compatibe to use FindMedium to get a IHardDisk object, even in
vbox old versions. To achieve this, first make FindMedium call
FindHardDisk when VBOX_API_VERSION < 4000000.
Then change the argument type **IMedium to **IHardDisk. (As the
rules in heriachy, we can't transfer a IHardDisk to match
IMedium in output)

In vbox 2.2 and 3.0, the caller must be aware that they will get
a IHardDisk object in return.

We use typedef IMedium IHardDisk to make IHardDisk hierachy from
IMedium (Actually it did on vbox 2.2 and 3.0's C++ API).
So when calling
    VBOX_MEDIUM_FUNC_ARG*(IHardDisk, func, args)
we can directly replace it to
    gVBoxAPI.UIMedium.func(IHardDisk, args)

When dealing with this two types, we get some rules from it's
hierachy relationship.

When using IHardDisk and IMedium as input, we can't transfer a
IMedium to IHardDisk. Like:
    gVBoxAPI.UIHardDisk.func(IHardDisk *hardDisk, args)
    Here, we can't put a *IMedium as a argument.

When using IHardDisk and IMedium as output, we can't transfer a
IHardDisk to IMedium. Like:
    gVBoxAPI.UIMachine.GetMedium(IMedium **out)
    Here, we can't put a **IHardDisk as a argument. If this case
    do happen, we either change the API to GetHardDisk or write a
    new one.

This patch rewrites the following functions
    *vboxStorageOpen
    *vboxStorageClose
    *vboxConnectNumOfStoragePools
    *vboxConnectListStoragePools
    *vboxStoragePoolLookupByName

These functions do not call any vbox API, so I directly move it
from vbox_tmpl.c to vbox_storage.c

A small improvement is made on vboxConnectListStoragePools.
The if condition nnames == 1 is modified to nnames > 0. So if the
caller put more than one slot to get active storage pools, the new
function will return exactly one, while the old one would only
return 0.

We should follow the rules that CHECK macro only do checking works.
But this VBOX_OBJECT_CHECK and VBOX_OBJECT_HOST_CHECK declared some
varibles at the same time, which broke the rule. So the patch
removed this macros and dispatched it in source code.

The storage driver is still not rewriten at this point. So, I
remains the VBOX_OBJECT_CHECK macro in vbox_tmpl.c. But this will
finally be removed in patch 'vbox: Remove unused things in vbox_tmpl.c'

To prepare for introducing a single global driver, rename the
virDriver struct to virHypervisorDriver and the registration
API to virRegisterHypervisorDriver()

This patch seperate the domain driver and the network driver.

libvirt_driver_vbox_impl.la has been linked in the network driver.
So that the version specified codes in vbox_V*.c would only be
compiled once.

The vboxGetNetworkDriver provides a simple interface to get vbox
network driver.

This patch rewrites two public APIs. They are vboxNetworkUndefine
and vboxNetworkDestroy. They use the same core function
vboxNetworkUndefineDestroy. I merged it in one patch.

This patch actually contains two public API, virNetworkDefineXML
and virNetworkCreateXML. They use the same core function
vboxNetworkDefineCreateXML. So I merged it together.

I'm about to add a syntax check that enforces our documented
HACKING style of always using matching {} on if-else statements.

This patch focuses on drivers that had several issues.

* src/lxc/lxc_fuse.c (lxcProcGetattr, lxcProcReadMeminfo): Correct
use of {}.
* src/lxc/lxc_driver.c (lxcDomainMergeBlkioDevice): Likewise.
* src/phyp/phyp_driver.c (phypConnectNumOfDomainsGeneric)
(phypUUIDTable_Init, openSSHSession, phypStoragePoolListVolumes)
(phypConnectListStoragePools, phypDomainSetVcpusFlags)
(phypStorageVolGetXMLDesc, phypStoragePoolGetXMLDesc)
(phypConnectListDefinedDomains): Likewise.
* src/vbox/vbox_common.c (vboxAttachSound, vboxDumpDisplay)
(vboxDomainRevertToSnapshot, vboxDomainSnapshotDelete): Likewise.
* src/vbox/vbox_tmpl.c (vboxStorageVolGetXMLDesc): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

After this patch, we will have only one common domain driver.
So, the rewritten on domain driver is finished in this patch.

Four functions are rewrite in this patch, that is:
vboxNodeGetInfo
vboxNodeGetCellsFreeMemory
vboxNodeGetFreeMemory
vboxNodeGetFreePages
Since these functions has nothing to do with vbox,
it can be directly moved to vbox_common.c. So, I
merged these things into one patch.