Revert "Fixed issue disqus#26"

Reverting this commit actually fixes disqus#26
This reverts commit 769f032.

bitfield/admin.py

@@ -1,13 +1,7 @@
-import six
-
-from django.db.models import F
-from django.core.exceptions import ValidationError
 from django.utils.translation import ugettext_lazy as _
 from django.contrib.admin import FieldListFilter
-from django.contrib.admin.options import IncorrectLookupParameters
 
 from bitfield import Bit
-from bitfield.compat import bitor
 
 
 class BitFieldListFilter(FieldListFilter):
@@ -23,13 +17,6 @@ def __init__(self, field, request, params, model, model_admin, field_path):
         super(BitFieldListFilter, self).__init__(
             field, request, params, model, model_admin, field_path)
 
-    def queryset(self, request, queryset):
-        filter = dict((p, bitor(F(p), v)) for p, v in six.iteritems(self.used_parameters))
-        try:
-            return queryset.filter(**filter)
-        except ValidationError as e:
-            raise IncorrectLookupParameters(e)
-
     def expected_parameters(self):
         return [self.lookup_kwarg]