Merge r1554161 from trunk:

mod_authnz_ldap: Support the expression parser within the require
directives.

Submitted by: minfrin
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1555539 13f79535-47bb-0310-9956-ffa450edef68