commit_message_check.py defaults to python3.4

Bug: None
Test: This upload
Change-Id: Idfed4f65722286cc9cfa14486369f21ed4990be4
diff --git a/tools/commit_message_check.py b/tools/commit_message_check.py
index 0fb413c..4bf60ee 100755
--- a/tools/commit_message_check.py
+++ b/tools/commit_message_check.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3.4
 #
 #   Copyright 2016 - The Android Open Source Project
 #