Deprecated SortedDict (replaced with collections.OrderedDict)

Thanks Loic Bistuer for the review.

django/contrib/staticfiles/storage.py

@@ -1,4 +1,5 @@
 from __future__ import unicode_literals
+from collections import OrderedDict
 import hashlib
 from importlib import import_module
 import os
@@ -16,7 +17,6 @@ from django.core.cache import (get_cache, InvalidCacheBackendError,
 from django.core.exceptions import ImproperlyConfigured
 from django.core.files.base import ContentFile
 from django.core.files.storage import FileSystemStorage, get_storage_class
-from django.utils.datastructures import SortedDict
 from django.utils.encoding import force_bytes, force_text
 from django.utils.functional import LazyObject
 from django.utils._os import upath
@@ -64,7 +64,7 @@ class CachedFilesMixin(object):
         except InvalidCacheBackendError:
             # Use the default backend
             self.cache = default_cache
-        self._patterns = SortedDict()
+        self._patterns = OrderedDict()
         for extension, patterns in self.patterns:
             for pattern in patterns:
                 if isinstance(pattern, (tuple, list)):
@@ -202,7 +202,7 @@ class CachedFilesMixin(object):
 
     def post_process(self, paths, dry_run=False, **options):
         """
-        Post process the given SortedDict of files (called from collectstatic).
+        Post process the given OrderedDict of files (called from collectstatic).
 
         Processing is actually two separate operations: