Add boilerplate from __future__ and type declarations

lib/ansible/module_utils/common/file.py

@@ -1,6 +1,9 @@
 # Copyright (c) 2018, Ansible Project
 # Simplified BSD License (see licenses/simplified_bsd.txt or https://opensource.org/licenses/BSD-2-Clause)
 
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
 import errno
 import os
 import stat
@@ -29,7 +32,7 @@ class LockTimeout(Exception):
     pass
 
 
-class FileLock():
+class FileLock:
     '''
     Currently FileLock is implemented via fcntl.flock on a lock file, however this
     behaviour may change in the future. Avoid mixing lock types fcntl.flock,