modify error

shanyi15 · web-flow · commit c55bff79697a · 2018-03-21T10:30:08.000+08:00
diff --git a/doc/fluid/design/dynamic_rnn/rnn.md b/doc/fluid/design/dynamic_rnn/rnn.md
@@ -149,5 +149,5 @@ If the `output_all_steps` is set to False, it will only output the final time st
 
 
 <p align="center">
-<img src="/rnn_2level_data.png"/>
+<img src="./rnn_2level_data.png"/>
 </p>
