virtio tools: add .gitignore

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tools/virtio/.gitignore

@@ -0,0 +1,3 @@
+*.d
+virtio_test
+vringh_test