PR61891: looping over mostly full LDAP cache

  *) mod_ldap: Fix a case where a full LDAP cache would continually fail to
     purge old entries and log AH01323. PR61891.



Submitted By: Hendrik Harms <hendrik.harms gmail.com>
Committed By: covener



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1818040 13f79535-47bb-0310-9956-ffa450edef68