Removed Django 1.10 deprecations.

https://docs.djangoproject.com/en/1.10/ref/models/meta/#migrating-from-the-old-api

Author: azmeuk

autoslug/utils.py

@@ -116,7 +116,7 @@ def get_uniqueness_lookups(field, instance, unique_with):
         value = getattr(instance, field_name)
         if not value:
             if other_field.blank:
-                field_object, model, direct, m2m = instance._meta.get_field_by_name(field_name)
+                field_object = instance._meta.get_field(field_name)
                 if isinstance(field_object, ForeignKey):
                     lookup = '%s__isnull' % field_name
                     yield lookup, True