TBR: update sg name as needed per v.io/c/15374

Change-Id: Iddfbea448133b7c94def15d72abff408c681039e
diff --git a/src/vanadium-wrapper/syncbase-wrapper.js b/src/vanadium-wrapper/syncbase-wrapper.js
index f704e99..4c2565d 100644
--- a/src/vanadium-wrapper/syncbase-wrapper.js
+++ b/src/vanadium-wrapper/syncbase-wrapper.js
@@ -276,7 +276,7 @@
     syncGroup: function(sgAdmin, name) {
       var self = this;
 
-      name = vanadium.naming.join(sgAdmin, '$sync', name);
+      name = vanadium.naming.join(sgAdmin, '@@sync', name);
       var sg = this.db.syncGroup(name);
 
       //syncgroup-promisified