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

client/tests/trace_inputs/touch_only.py

 #!/usr/bin/env python
-# Copyright 2012 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 2012 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.
 
 """Uses different APIs to touch a file."""
 
 import os
 import sys
 
 
 BASE_DIR = os.path.dirname(os.path.abspath(__file__))
 
 
 def main():
   print 'Only look if a file exists but do not open it.'
   assert len(sys.argv) == 2
   path = os.path.join(BASE_DIR, 'test_file.txt')
   command = sys.argv[1]
   if command == 'access':
     return not os.access(path, os.R_OK)
   elif command == 'isfile':
     return not os.path.isfile(path)
   elif command == 'stat':
     return not os.stat(path).st_size
   return 1
 
 
 if __name__ == '__main__':
   sys.exit(main())