don't forget base_url when updating address bar in rename

IPython/html/static/notebook/js/savewidget.js

@@ -126,15 +126,17 var IPython = (function (IPython) {
     };
     
     SaveWidget.prototype.update_address_bar = function(){
+        var base_url = IPython.notebook.base_url;
         var nbname = IPython.notebook.notebook_name;
         var path = IPython.notebook.notebook_path;
-        var state = {path : utils.url_join_encode(path, nbname)};
+        var state = {path : path, name: nbname};
         window.history.replaceState(state, "", utils.url_join_encode(
-            "/notebooks",
+            base_url,
+            "notebooks",
             path,
             nbname)
         );
-    }
+    };
 
 
     SaveWidget.prototype.set_save_status = function (msg) {