Fixed #15043 -- Updated the login function to send the user_logged_in signal...

Fixed #15043 -- Updated the login function to send the user_logged_in signal after the user's session got recycled instead of before. Thanks, Rob Hudson.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15168 bcc190cf-cafb-0310-a4f2-bffc1f526a37