Topo2: Update links on websocket events

Change-Id: I6a8b05cc0eaf67e2b10dd39aeb4b876c61c40ec6
diff --git a/web/gui/src/main/webapp/app/view/topo2/topo2Layout.js b/web/gui/src/main/webapp/app/view/topo2/topo2Layout.js
index 9849393..2f6f0d2 100644
--- a/web/gui/src/main/webapp/app/view/topo2/topo2Layout.js
+++ b/web/gui/src/main/webapp/app/view/topo2/topo2Layout.js
@@ -256,7 +256,7 @@
                         var regionLinks = t2rs.regionLinks();
 
                         this.link = this.elements.linkG.selectAll('.link')
-                            .data(regionLinks, function (d) { return d.get('key'); });
+                            .data(regionLinks);
 
                         // operate on entering links:
                         var entering = this.link.enter()