Replace test use of assertTrue with failUnless. No matter how many times we try, Python 2.3 still doesn't recognize assertTrue.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10390 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/model_formsets/tests.py

@@ -15,7 +15,7 @@ class DeletionTests(TestCase):
         }
         formset = PoetFormSet(data, queryset=Poet.objects.all())
         formset.save()
-        self.assertTrue(formset.is_valid())
+        self.failUnless(formset.is_valid())
         self.assertEqual(Poet.objects.count(), 0)
 
     def test_add_form_deletion_when_invalid(self):