qemu: Perform the disk WWN check only on fresh starts
qemu: Perform the disk WWN check only on fresh starts

Since we'd disallow migration of a guest that would have possibly
invalid config but still be able to work, relax the WWN check to be
performed only on new starts of the VM.

rlaager/libvirt,datto/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,jardasgit/libvirt,jardasgit/libvirt,andreabolognani/libvirt,eskultety/libvirt,andreabolognani/libvirt,libvirt/libvirt,rlaager/libvirt,olafhering/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,taget/libvirt,libvirt/libvirt,nertpinx/libvirt,jfehlig/libvirt,datto/libvirt,taget/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,jardasgit/libvirt,zippy2/libvirt,taget/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,VenkatDatta/libvirt,eskultety/libvirt,crobinso/libvirt,jardasgit/libvirt,olafhering/libvirt,rlaager/libvirt,eskultety/libvirt,datto/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,eskultety/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,taget/libvirt,olafhering/libvirt,crobinso/libvirt,nertpinx/libvirt,libvirt/libvirt,VenkatDatta/libvirt,taget/libvirt,libvirt/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,andreabolognani/libvirt,zippy2/libvirt,crobinso/libvirt,eskultety/libvirt,zippy2/libvirt,rlaager/libvirt,zippy2/libvirt,rlaager/libvirt,jfehlig/libvirt,datto/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,datto/libvirt,olafhering/libvirt,crobinso/libvirt