ldap: add notice about TLS options (#4608)

Author: remicollet

reference/ldap/functions/ldap-set-option.xml

@@ -208,6 +208,13 @@
        xlink:href="&url.ldap.openldap-c-api;">draft-ietf-ldapext-ldap-c-api-xx.txt</link>
        for details. See also the second example below.
       </para>
+      <note>
+       <para>
+       All TLS options must be set globally before
+       <function>ldap_connect</function> for ldaps connection or
+       for the connection before <function>ldap_start_tls</function>.
+       </para>
+      </note>
      </listitem>
     </varlistentry>
     <varlistentry>