Fixed #7602 -- Corrected lookup keyword arguments in archive_month and archive_week to properly range when date_field is from DateField. Thanks nullie for the original patch and Colin Grady for the test coverage.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8476 bcc190cf-cafb-0310-a4f2-bffc1f526a37