qemu_hotplug: Fetch vhostuser ifname on hotplug
qemu_hotplug: Fetch vhostuser ifname on hotplug

https://bugzilla.redhat.com/show_bug.cgi?id=1630164

Since 2a13a0a1033 we are querying the vhostuser's interface name
when building qemu command line. However, we forgot to do so on
hotplug.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>

jardasgit/libvirt,andreabolognani/libvirt,eskultety/libvirt,fabianfreyer/libvirt,crobinso/libvirt,zippy2/libvirt,eskultety/libvirt,eskultety/libvirt,andreabolognani/libvirt,libvirt/libvirt,libvirt/libvirt,crobinso/libvirt,jardasgit/libvirt,olafhering/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,jardasgit/libvirt,nertpinx/libvirt,jfehlig/libvirt,andreabolognani/libvirt,jfehlig/libvirt,jfehlig/libvirt,nertpinx/libvirt,zippy2/libvirt,nertpinx/libvirt,andreabolognani/libvirt,jfehlig/libvirt,zippy2/libvirt,jardasgit/libvirt,libvirt/libvirt,crobinso/libvirt,olafhering/libvirt,fabianfreyer/libvirt,eskultety/libvirt,eskultety/libvirt,andreabolognani/libvirt,zippy2/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,crobinso/libvirt,fabianfreyer/libvirt,olafhering/libvirt,nertpinx/libvirt,olafhering/libvirt,libvirt/libvirt