vz: fix typo that lost the '#' in '#define'

Previous commit:

  commit faceedaf
  Author: Jonathon Jongsma <jjongsma@redhat.com>
  Date:   Tue Jun 18 11:13:12 2019 -0500

    src/vz: use #pragma once in headers

accidentally chomped the "#" in a "#define" when re-indenting

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>