find python via env

This allows these scripts to run through the active version of the
virtualenv python when invoked via tox.

Change-Id: Ib52f475b7b20c34d62cfd179a1341da1a08a8b5c
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/253974
Reviewed-by: David Pursehouse <dpursehouse@collab.net>
Tested-by: Mike Frysinger <vapier@google.com>
diff --git a/run_tests b/run_tests
index 1b35ade..d7144b3 100755
--- a/run_tests
+++ b/run_tests
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding:utf-8 -*-
 # Copyright 2019 The Android Open Source Project
 #
diff --git a/setup.py b/setup.py
index e48aa30..f4d7728 100755
--- a/setup.py
+++ b/setup.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding:utf-8 -*-
 # Copyright 2019 The Android Open Source Project
 #