Fixed filter_horizontal and filter_vertical handling in admin so that they can

be lists (aren't required to be tuples). It's less error-prone to use one item
lists than one-tuples, but this caused a crash.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8011 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/admin/options.py

@@ -165,7 +165,7 @@ class BaseModelAdmin(object):
                     if db_field.name in self.raw_id_fields:
                         kwargs['widget'] = widgets.ManyToManyRawIdWidget(db_field.rel)
                         kwargs['help_text'] = ''
-                    elif db_field.name in (self.filter_vertical + self.filter_horizontal):
+                    elif db_field.name in (list(self.filter_vertical) + list(self.filter_horizontal)):
                         kwargs['widget'] = widgets.FilteredSelectMultiple(db_field.verbose_name, (db_field.name in self.filter_vertical))
             # Wrap the widget's render() method with a method that adds
             # extra HTML to the end of the rendered output.