[1.2.X] Updated AJAX example code in CSRF docs to be consistent regarding what...

[1.2.X] Updated AJAX example code in CSRF docs to be consistent regarding what are safe HTTP methods

Backport of [16202] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@16204 bcc190cf-cafb-0310-a4f2-bffc1f526a37