Removed an import that is no longer needed after r13033.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13035 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/bug8245/tests.py

-import sys
 from unittest import TestCase
 
 from django.contrib import admin