docfix apache2 now supports client chunked encodin

As reported in the documentation bug, the apache deployment guide's
reference to apache2 mod_wsgi not supporting client chunked encoding
has become outdated. It now supports this feature, using an optional
parameter.

Updated the paragraph in question to reflect this

patchset 2 mentions the WSGIChunkedRequest variable and adds it
to the sample configs - On by default. Feedback welcome

fixes bug 1194935

Change-Id: I07c5c8506ac34e1e0e08fa6d961babde2f9b7367
Merge "docfix apache2 now supports client chunked encodin"