Update copyright notice from Swarming to LUCI; add AUTHORS and CONTRIBUTORS.

client/tests/on_error_test.py

 #!/usr/bin/env python
-# Copyright 2014 The Swarming Authors. All rights reserved.
-# Use of this source code is governed under the Apache License, Version 2.0 that
-# can be found in the LICENSE file.
+# Copyright 2014 The LUCI Authors. All rights reserved.
+# Use of this source code is governed by the Apache v2.0 license that can be
+# found in the LICENSE file.
 
 import BaseHTTPServer
 import atexit
 import cgi
 import getpass
 import json
 import logging
 import os
 import platform
 import re
@@ skipping 396 matching lines @@
   os.environ.pop(on_error._DISABLE_ENVVAR, None)
 
   if len(sys.argv) == 4 and sys.argv[1] == 'run_shell_out':
     sys.exit(run_shell_out(sys.argv[2], sys.argv[3]))
 
   if '-v' in sys.argv:
     unittest.TestCase.maxDiff = None
   logging.basicConfig(
       level=logging.DEBUG if '-v' in sys.argv else logging.ERROR)
   unittest.main()