ref/services/syncbase: Move to using the new XServer API.

Change-Id: Ib00ed98a93a0f26d61b9b88356ab4c759dac9970
diff --git a/services/syncbase/vsync/syncgroup.go b/services/syncbase/vsync/syncgroup.go
index c9263f1..7225404 100644
--- a/services/syncbase/vsync/syncgroup.go
+++ b/services/syncbase/vsync/syncgroup.go
@@ -770,7 +770,7 @@
 		name := naming.Join(mt, ss.name)
 		// TODO(hpucha): Is this add idempotent? Appears to be from code.
 		// Confirm that it is ok to use absolute names here.
-		if err := ss.server.AddName(name); err != nil {
+		if err := call.Server().AddName(name); err != nil {
 			return err
 		}
 	}