qemuDomainAttachHostPCIDevice: Handle hostevs with unassigned type of address
qemuDomainAttachHostPCIDevice: Handle hostevs with unassigned type of address

A <hostdev/> can have <address type='unassigned'/> which means
libvirt manages the device detach from/reattach to the host but
the device is never exposed to the guest. This means that we have
to take a shortcut during hotplug, similar to the one we are
taking when constructing the command line (see
qemuBuildHostdevCommandLine()).

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2040548
Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

crobinso/libvirt,crobinso/libvirt,olafhering/libvirt,zippy2/libvirt,olafhering/libvirt,crobinso/libvirt,libvirt/libvirt,jfehlig/libvirt,libvirt/libvirt,jfehlig/libvirt,crobinso/libvirt,libvirt/libvirt,zippy2/libvirt,olafhering/libvirt,jfehlig/libvirt,olafhering/libvirt,libvirt/libvirt,zippy2/libvirt,jfehlig/libvirt,zippy2/libvirt