Create a separate typedef for the hostdev union data describing USB.
Then adjust the code to use the new pointer

Since it is an abbreviation, PCI should always be fully
capitalized or full lower case, never Pci.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Without this, session libvirt won't start if it fails to create
the directory.

The object itself is freed by virObjectUnref.

Any source file which calls the logging APIs now needs
to have a VIR_LOG_INIT("source.name") declaration at
the start of the file. This provides a static variable
of the virLogSource type.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add VIR_DOMAIN_HOSTDEV_PCI_BACKEND_XEN. For legacy xen, it will use "pciback" as
stub driver.

Mark many parameters as NONNULL and check for empty list of
hostdevs.

Changes parameter from vm def to specific hostdevs info and name info, so that
it could be used more widely, e.g, could be used without full vm def info.

Change any variable names with Usb, Pci or Scsi to use
USB, PCI and SCSI since they are abbreviations.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Some virHostdevXXXX methods included the string Hostdev again
as a suffix. Change the latter to Device instead.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Change any method names with Usb, Pci or Scsi to use
USB, PCI and SCSI since they are abbreviations.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Various methods in virnetdev.c and virhostdev.c were missing
const-ness for several char * parameters.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Use virObject to virHostdevManager, so that each driver using virHostdevManager
can keep a reference to it, and through counting refs to make virHostdevManager
get freed.

Signed-off-by: NChunyan Liu <cyliu@suse.com>