Fixed #2036 -- autoreload.py no longer fails for uninstalled 'thread' module....

Fixed #2036 -- autoreload.py no longer fails for uninstalled 'thread' module. Thanks, plmeister@gmail.com

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3020 bcc190cf-cafb-0310-a4f2-bffc1f526a37