Update module_utils.six to latest (#22855)

* Update module_utils.six to latest

We've been held back on the version of six we could use on the module
side to 1.4.x because of python-2.4 compatibility.  Now that our minimum
is Python-2.6, we can update to the latest version of six in
module_utils and get rid of the second copy in lib/ansible/compat.

lib/ansible/plugins/connection/__init__.py

@@ -24,23 +24,21 @@ import gettext
 import os
 import shlex
 from abc import ABCMeta, abstractmethod, abstractproperty
-
 from functools import wraps
-from ansible.compat.six import with_metaclass
 
 from ansible import constants as C
-from ansible.compat.six import string_types
 from ansible.errors import AnsibleError
+from ansible.module_utils.six import string_types, with_metaclass
 from ansible.module_utils._text import to_bytes, to_text
 from ansible.plugins import shell_loader
 
-
 try:
     from __main__ import display
 except ImportError:
     from ansible.utils.display import Display
     display = Display()
 
+
 __all__ = ['ConnectionBase', 'ensure_connect']
 
 BUFSIZE = 65536