Apply suggestions from code review

Author: fsbraun

filer/utils/files.py

@@ -2,7 +2,6 @@
 import os
 import uuid
 
-from django.conf import settings
 from django.http.multipartparser import ChunkIter, SkipFile, StopFutureHandlers, StopUpload, exhaust
 from django.template.defaultfilters import slugify as slugify_django
 from django.utils.encoding import force_str

tests/test_files.py

@@ -1,6 +1,5 @@
 import string
 
-from django.conf import settings
 from django.test import TestCase
 from filer.utils.files import get_valid_filename