"LDAPReferrals off" does not disable LDAPReferrals feature. Default OpenLDAP value for LDAP_OPT_REFERRALS is ON and the current code does not set it to OFF even when there is "LDAPReferrals off" directive in the config file.

Changes LDAPReferrals to tri-state:

- "on" - default. Calls apr_ldap_set_option to set referrals on.
- "off" - Calls apr_ldap_set_option to turn referrals off.
- "default" - Does not call apr_ldap_set_option at all.


The default remains ON.  If "default" and SDK defaults to ON, no rebind callback 
is used.

Submitted By: Jan Kaluza <kaluze AT redhat.com>
Committed By: covener


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1517388 13f79535-47bb-0310-9956-ffa450edef68