Fixed #15622 -- Clear content type cache to avoid problems with subse…

…quence TransactionTestCases. Thanks to zyga for the report

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15867 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/contenttypes/tests.py

@@ -22,6 +22,7 @@ def setUp(self):
     def tearDown(self):
         settings.DEBUG = self.old_DEBUG
         Site._meta.installed = self.old_Site_meta_installed
+        ContentType.objects.clear_cache()
 
     def test_lookup_cache(self):
         """