qemu_driver: check whether iothread is used by controller
qemu_driver: check whether iothread is used by controller

This follows the same check for disk, because we cannot remove iothread
if it's used by disk or by controller.  It could lead to crashing QEMU.

Signed-off-by: Pavel Hrdina <d4772d05997b8abf035041e3b4f4996380ea7e7a@redhat.com>

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