Fixed #15067 -- Modified the range checks on base36_to_int so you are...

Fixed #15067 -- Modified the range checks on base36_to_int so you are guaranteed to always get an int, avoiding possible OverflowErrors. Thanks to Garthex for the report, jboutros for the patch, and kfrazier for the feedback.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15288 bcc190cf-cafb-0310-a4f2-bffc1f526a37