Tweaked [531] slightly, so that it checks for 'is None' instead of boolean 'not'

git-svn-id: http://code.djangoproject.com/svn/django/trunk@532 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/handlers/base.py

@@ -64,7 +64,7 @@ class BaseHandler:
             response = callback(request, **param_dict)
 
             # Complain if the view returned None (a common error).
-            if not response:
+            if response is None:
                 raise ValueError, "The view %s.%s didn't return an HttpResponse object." % (callback.__module__, callback.func_name)
 
             return response