backport r881808 from trunk:

    Add AuthLDAPBindAuthoritative to allow other authentication providers a chance
    to run when mod_authnz_ldap finds a user but can't verify their password.

Submitted By: Justin Erenkrantz, Joe Schaefer, Tony Stevenson
Reviewed By: covener, pgollucci, rpluem



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@916091 13f79535-47bb-0310-9956-ffa450edef68