Fix mod_auth_*.html documents: NSCA -> NCSA

Submitted by: Youichirou Koga <y-koga@jp.FreeBSD.org>
PR: 2991


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82036 13f79535-47bb-0310-9956-ffa450edef68