The libvirtd daemon impl will need to switch over to using the
new event APIs. To make this simpler, ensure all drivers currently
providing events support both the new APIs and old APIs.

* src/lxc/lxc_driver.c, src/qemu/qemu_driver.c, src/test/test_driver.c,
  src/vbox/vbox_tmpl.c, src/xen/xen_driver.c: Implement the new
  virConnectDomainEvent(Dereg|Reg)isterAny driver entry points