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.

test/units/parsing/test_dataloader.py

@@ -19,12 +19,11 @@
 from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
-from six import PY3
-
 from ansible.compat.tests import unittest
 from ansible.compat.tests.mock import patch, mock_open
 from ansible.errors import AnsibleParserError
 from ansible.errors import yaml_strings
+from ansible.module_utils.six import PY3
 
 from ansible.parsing.dataloader import DataLoader
 

test/units/parsing/vault/test_vault.py

@@ -21,8 +21,6 @@
 from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
-import six
-
 import binascii
 import io
 import os
@@ -33,9 +31,10 @@ from nose.plugins.skip import SkipTest
 from ansible.compat.tests import unittest
 
 from ansible import errors
+from ansible.module_utils import six
+from ansible.module_utils._text import to_bytes, to_text
 from ansible.parsing.vault import VaultLib
 from ansible.parsing import vault
-from ansible.module_utils._text import to_bytes, to_text
 
 
 # Counter import fails for 2.0.1, requires >= 2.6.1 from pip

test/units/parsing/yaml/test_loader.py

@@ -22,12 +22,12 @@ __metaclass__ = type
 
 from io import StringIO
 
-from six import text_type, binary_type
 from collections import Sequence, Set, Mapping
 
 from ansible.compat.tests import unittest
 
 from ansible import errors
+from ansible.module_utils.six import text_type, binary_type
 from ansible.parsing.yaml.loader import AnsibleLoader
 from ansible.parsing import vault
 from ansible.parsing.yaml.objects import AnsibleVaultEncryptedUnicode