Changed all model unit tests to use __str__() instead of __repr__(). Also slightly changed related-object DoesNotExist exception message to use repr instead of str

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3075 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/validation/models.py

@@ -17,7 +17,7 @@ class Person(models.Model):
     favorite_moment = models.DateTimeField()
     email = models.EmailField()
 
-    def __repr__(self):
+    def __str__(self):
         return self.name
 
 API_TESTS = """