[Open Screen] Remove calls to python from DEPS.

Most of the scripts we use in DEPS already have correct shebang lines,
and don't need to be invoked with python3.

The exception is clang-update.py, which we download and run, and we
can't reliably set it to be executable on Windows.

This also fixes curlish.py to be py3 compatible.

Bug: b/195416694
Change-Id: If119386666364a56e833d0f6207437f1f5454d23
Reviewed-on: https://chromium-review.googlesource.com/c/openscreen/+/3253431
Commit-Queue: Jordan Bayles <jophba@chromium.org>
Reviewed-by: Jordan Bayles <jophba@chromium.org>
diff --git a/DEPS b/DEPS
index b020959..8ea6555 100644
--- a/DEPS
+++ b/DEPS
@@ -170,7 +170,7 @@
     'name': 'clang_update_script',
     'pattern': '.',
     'condition': 'not build_with_chromium',
-    'action': [ 'python', 'tools/download-clang-update-script.py',
+    'action': [ 'tools/download-clang-update-script.py',
                 '--output', 'tools/clang/scripts/update.py' ],
     # NOTE: This file appears in .gitignore, as it is not a part of the
     # openscreen repo.
@@ -179,7 +179,7 @@
     'name': 'yajsv_update_script',
     'pattern': '.',
     'condition': 'not build_with_chromium',
-    'action': [ 'python', 'tools/download-yajsv.py' ],
+    'action': [ 'tools/download-yajsv.py' ],
   },
   {
     'name': 'update_clang',
diff --git a/tools/curlish.py b/tools/curlish.py
index 956c5c4..2f1d321 100755
--- a/tools/curlish.py
+++ b/tools/curlish.py
@@ -1,4 +1,3 @@
-#!/usr/bin/env python3
 # Copyright 2020 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
@@ -8,12 +7,8 @@
 """
 
 import os
-
-try:
-    from urllib2 import HTTPError, URLError, urlopen
-except ImportError:  # For Py3 compatibility
-    from urllib.error import HTTPError, URLError
-    from urllib.request import urlopen
+from urllib.error import HTTPError, URLError
+from urllib.request import urlopen
 
 
 def curlish(download_url, output_path):
@@ -41,8 +36,7 @@
     if not os.path.exists(directory):
         os.makedirs(directory)
 
-    script_file = open(output_path, 'w')
-    script_file.write(script_contents)
-    script_file.close()
+    with open(output_path, 'wb') as script_file:
+        script_file.write(script_contents)
 
     return True