Fixed #15531 -- Partially reverted [15701] due to compatibility issues with...

Fixed #15531 -- Partially reverted [15701] due to compatibility issues with middlewares that modify content of responses. Thanks for the report, schinckel. Refs #15281.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15703 bcc190cf-cafb-0310-a4f2-bffc1f526a37