Some tools, such as virt-manager, prefers having the default USB
controller explicit in the XML document. This patch makes sure there
is one. With this patch, it is now possible to switch from USB1 to
USB2 from the release 0.9.1 of virt-manager.
Fix tests to pass with this change.
KVM will be able to use a PCI SCSI controller even on POWER. Let
the user specify the vSCSI controller by other means than a default.
After this patch, the QEMU driver will actually look at the model
and reject anything but auto, lsilogic and ibmvscsi.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
