convert shebang lines: python -> python3
diff --git a/Tools/scripts/dutree.py b/Tools/scripts/dutree.py
index dbf4f1a..6b4361a 100755
--- a/Tools/scripts/dutree.py
+++ b/Tools/scripts/dutree.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 # Format du output in a tree shape
 
 import os, sys, errno