[1.2.X] Fixed #14225 -- Added a documentation marker (and a 1.2.2 release...

[1.2.X] Fixed #14225 -- Added a documentation marker (and a 1.2.2 release notes file, required to satisfy Sphinx) for the enable_csrf_checks flag on the test client. Thanks to public@grep.ro for the report.

Backport of r14011 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14022 bcc190cf-cafb-0310-a4f2-bffc1f526a37