Fix the expressions modeltest to work on Pythons earlier than 2.5.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11423 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/expressions/models.py

@@ -117,6 +117,6 @@ FieldError: Joined field references are not permitted in this query
 >>> acme.save()
 Traceback (most recent call last):
 ...
-TypeError: int() argument must be a string or a number, not 'ExpressionNode'
+TypeError: int() argument must be a string or a number...
 
 """}