add nova filter for flake8

pipeline/manifest.py

 try:
     from staticfiles.finders import DefaultStorageFinder
 except ImportError:
-    from django.contrib.staticfiles.storage import DefaultStorageFinder
+    from django.contrib.staticfiles.storage import DefaultStorageFinder # noqa
 
 from django.conf import settings
 

pipeline/storage.py

@@ -4,8 +4,8 @@ try:
     from staticfiles import finders
     from staticfiles.storage import CachedFilesMixin, StaticFilesStorage
 except ImportError:
-    from django.contrib.staticfiles import finders
-    from django.contrib.staticfiles.storage import CachedFilesMixin, StaticFilesStorage
+    from django.contrib.staticfiles import finders # noqa
+    from django.contrib.staticfiles.storage import CachedFilesMixin, StaticFilesStorage # noqa
 
 from django.core.exceptions import ImproperlyConfigured
 from django.core.files.storage import get_storage_class

pipeline/templatetags/compressed.py

 try:
     from staticfiles.storage import staticfiles_storage
 except ImportError:
-    from django.contrib.staticfiles.storage import staticfiles_storage
+    from django.contrib.staticfiles.storage import staticfiles_storage # noqa
 
 from django import template
 from django.template.loader import render_to_string