djang.http.HttpResponse logic for _is_string is invalid

[(removed)]

code currently does effectively thus-
if hasattr(content, 'iter'):

self._is_string = False
self._container = content

else:

self._is_string = True
self._container = [content]

Problem is that string objects support iteration.

Fix for it's simple; just do

if not isinstance(content, basestring) and hasattr(content, 'iter'):

(yes y'all prefer seperate patches, but it's a one liner ;)