Fixed runtest to work with python != 2.4

Change-Id: I6104adb5a6549eb4eaa3f2096633a49e4743ce50
diff --git a/testrunner/runtest.py b/testrunner/runtest.py
index be94437..f7a4759 100755
--- a/testrunner/runtest.py
+++ b/testrunner/runtest.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python2.4
+#!/usr/bin/env python
 #
 # Copyright 2008, The Android Open Source Project
 #