Add error code 123 from RFC4370

lib/errors/index.js

@@ -46,7 +46,8 @@ var CODES = {
   LDAP_ENTRY_ALREADY_EXISTS: 68,
   LDAP_OBJECTCLASS_MODS_PROHIBITED: 69,
   LDAP_AFFECTS_MULTIPLE_DSAS: 71,
-  LDAP_OTHER: 80
+  LDAP_OTHER: 80,
+  LDAP_PROXIED_AUTHORIZATION_DENIED: 123
 };
 
 var ERRORS = [];