scsi-disk: qemu_vfree(NULL) is fine, simplify Signed-off-by: Markus Armbruster <armbru@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>