Fixed #15524 -- Marked up for translation literal shown by the admin …

…app e.g. in nullable changelist cells and filters. Thanks charettes for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15698 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/admin/views/main.py

@@ -24,7 +24,7 @@
 ERROR_FLAG = 'e'
 
 # Text to display within change-list table cells if the value is blank.
-EMPTY_CHANGELIST_VALUE = '(None)'
+EMPTY_CHANGELIST_VALUE = ugettext('(None)')
 
 class ChangeList(object):
     def __init__(self, request, model, list_display, list_display_links, list_filter, date_hierarchy, search_fields, list_select_related, list_per_page, list_editable, model_admin):