magic-removal: Improved 'properties' model unit tests to test for setting attribute on a property

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@1619 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/properties/models.py

@@ -16,5 +16,11 @@ API_TESTS = """
 >>> a = Person(first_name='John', last_name='Lennon')
 >>> a.save()
 >>> a.full_name
-John Lennon
+'John Lennon'
+
+# The "full_name" property hasn't provided a "set" method.
+>>> a.full_name = 'Paul McCartney'
+Traceback (most recent call last):
+    ...
+AttributeError: can't set attribute
 """