Enhance the FAQ with info about "I wanna use /etc/passwd for Web

authentication", and inadvertent POST restriction by omitting the
method from <Limit> blocks.  (Many thanks to Rob H and Marc S for
portions of the former.)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@77817 13f79535-47bb-0310-9956-ffa450edef68