Add option to redirect_to view to allow passing along the query string

from the original request. Default is current behaviour, which is not to
pass the query string (it often won't be appropriate to do so).

Thanks to steingrd@ifi.uio.no for the patch and tests. Fixed #9966.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13746 bcc190cf-cafb-0310-a4f2-bffc1f526a37