Fix python interpreter.
diff --git a/build_images.py b/build_images.py
index 9dec613..a5ca48a 100755
--- a/build_images.py
+++ b/build_images.py
@@ -1,4 +1,5 @@
-#!/usr/bin/env python
+#!/usr/bin/python
+
 # Copyright (C) 2012 Linaro
 #
 # Author: Andy Doan <andy.doan@linaro.org>