minor fix

theano/gof/compiledir.py

@@ -207,7 +207,7 @@ def filter_compiledir(path):
                 pass  # has already been created
             else:
                 if os.path.exists(path):
-                    e.args += ('%d does not exist..' % path,)
+                    e.args += ('%s does not exist..' % path,)
                 raise
     return path