strip_package: Run on Python 3

This script has few dependencies and can easily run on Python 3 with
minor cleanups.

BUG=chromium:998225, chromium:1114277
TEST=`builder_test.py`

Change-Id: Ib01f1361eebf8c010bb079d8e50902db9e2c1ccf
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2350119
Reviewed-by: Congbin Guo <guocb@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Tested-by: Chris McDonald <cjmcdonald@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/builder.py b/builder.py
index 7d6c62f..200cb35 100644
--- a/builder.py
+++ b/builder.py
@@ -250,5 +250,5 @@
         return self.SetError('Package %s is not installed' % pkg)
 
       return 'Success\n'
-    except OSError, e:
+    except OSError as e:
       return self.SetError('Could not execute build command: ' + str(e))
diff --git a/strip_package.py b/strip_package.py
index 60bb25a..1ca70d4 100755
--- a/strip_package.py
+++ b/strip_package.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python2
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 # Copyright (c) 2009-2015 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be