Show in the logs if group sync is disabled

src/externalldap.js

@@ -129,7 +129,10 @@ function ldapGroupSearch(externalLdapConfig, options, callback) {
     assert.strictEqual(typeof options, 'object');
     assert.strictEqual(typeof callback, 'function');
 
-    if (!externalLdapConfig.syncGroups) return callback(null, []);
+    if (!externalLdapConfig.syncGroups) {
+        debug('Group sync is disabled');
+        return callback(null, []);
+    }
 
     getClient(externalLdapConfig, function (error, client) {
         if (error) return callback(error);