Removed cases of six.iter* wrapped in a list()

There's absolutely no advantage [and a mild performance hit] to using six.iter*
in these cases.

django/utils/functional.py

@@ -184,7 +184,7 @@ def allow_lazy(func, *resultclasses):
 
     @wraps(func)
     def wrapper(*args, **kwargs):
-        for arg in list(args) + list(six.itervalues(kwargs)):
+        for arg in list(args) + list(kwargs.values()):
             if isinstance(arg, Promise):
                 break
         else: