It's only printing a warning since QEMU v1.3.0, so nobody should use
this anymore today. Let's get rid of this now.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1513619065-31722-1-git-send-email-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>