Fixed #20080 - Recommended use of PYTHONHASHSEED

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This setting is required if you're using the :ttag:`ssi` template tag.

Python Options

==============

If you're using Python 2.6.8+, it's strongly recommended that you invoke the

Python process running your Django application using the `-R`_ option or with

the :envvar:`PYTHONHASHSEED` environment variable set to ``random``.

These options help protect your site from denial-of-service (DoS)

attacks triggered by carefully crafted inputs. Such an attack can

drastically increase CPU usage by causing worst-case performance when

creating ``dict`` instances. See `oCERT advisory #2011-003

<http://www.ocert.org/advisories/ocert-2011-003.html>`_ for more information.

.. _-r: http://docs.python.org/2.7/using/cmdline.html#cmdoption-R