nv20: draw_elements needs to flush

nv20_draw_elements() uses the draw module, and draw_flush() needs to be
called to actually emit the vertices immediately.

Signed-off-by: Pekka Paalanen <pq@iki.fi>

src/gallium/drivers/nv20/nv20_vbo.c

@@ -64,6 +64,7 @@ boolean nv20_draw_elements( struct pipe_context *pipe,
 		draw_set_mapped_element_buffer(draw, 0, NULL);
 	}
 
+	draw_flush(nv20->draw);
 	return TRUE;
 }