Fixed #4969 -- Changed content retrieval in HttpResponse to be more robust in

the presence of an existing content encoding. Fixes some sporadic failures with
the GzipMiddleware, for example. Thanks, Johann Queuniet.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@6548 bcc190cf-cafb-0310-a4f2-bffc1f526a37