Stop requiring six as a depdendency.

This is possible now that we require at least a version of Django that ships with six.

Signed-off-by: Jannis Leidel <jannis@leidel.info>

constance/admin.py

@@ -2,7 +2,6 @@ from datetime import datetime, date, time
 from decimal import Decimal
 import hashlib
 from operator import itemgetter
-import six
 
 from django import forms
 from django.contrib import admin, messages
@@ -13,6 +12,7 @@ from django.forms import fields
 from django.http import HttpResponseRedirect
 from django.shortcuts import render_to_response
 from django.template.context import RequestContext
+from django.utils import six
 from django.utils.formats import localize
 from django.utils.translation import ugettext_lazy as _
 

constance/backends/redisd.py

@@ -1,7 +1,6 @@
-import six
-from six.moves import zip
-
 from django.core.exceptions import ImproperlyConfigured
+from django.utils import six
+from django.utils.six.moves import zip
 
 from . import Backend
 from .. import settings, utils

setup.py

@@ -50,7 +50,6 @@ setup(
     ],
     packages=find_packages(exclude=['tests', 'tests.*']),
     include_package_data=True,
-    install_requires=['six'],
     zip_safe=False,
     extras_require={
         'database': ['django-picklefield'],

tests/settings.py

@@ -1,6 +1,7 @@
 # -*- encoding: utf-8 -*-
 import django
-import six
+from django.utils import six
+
 from datetime import datetime, date, time
 from decimal import Decimal
 

tests/storage.py

@@ -1,7 +1,7 @@
 # -*- encoding: utf-8 -*-
-import six
 from datetime import datetime, date, time
 from decimal import Decimal
+from django.utils import six
 
 if six.PY3:
     def long(value):