fix typo

server/server.py

@@ -131,7 +131,7 @@ class JudgeServer(object):
             logger.exception(e)
             ret = dict()
             ret["err"] = e.__class__.__name__
-            ret["data"] = e.message
+            ret["data"] = str(e)
             return json.dumps(ret)
         except Exception as e:
             logger.exception(e)
@@ -156,4 +156,4 @@ wsgiapp = app.wsgifunc()
 
 # gunicorn -w 4 -b 0.0.0.0:8080 server:wsgiapp
 if __name__ == "__main__":
-    app.run()
+    app.run()