Remove six package and dependent code

helpdesk/tests/test_get_email.py

@@ -18,7 +18,6 @@ import itertools
 import logging
 import os
 from shutil import rmtree
-import six
 import sys
 from tempfile import mkdtemp
 import typing
@@ -376,7 +375,7 @@ class GetEmailParametricTemplate(object):
             if self.method == 'local':
                 with mock.patch('os.listdir') as mocked_listdir, \
                         mock.patch('helpdesk.email.isfile') as mocked_isfile, \
-                        mock.patch('builtins.open' if six.PY3 else '__builtin__.open', mock.mock_open(read_data=test_email)), \
+                        mock.patch('builtins.open', mock.mock_open(read_data=test_email)), \
                         mock.patch('os.unlink'):
                     mocked_isfile.return_value = True
                     mocked_listdir.return_value = ['filename1', 'filename2']

requirements.txt

@@ -8,7 +8,6 @@ beautifulsoup4
 lxml
 simplejson
 pytz
-six
 pinax_teams
 djangorestframework
 django-model-utils