update polymer components

dashboard-ui/bower_components/iron-selector/iron-multi-selectable.html

@@ -72,6 +72,11 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
       this._selection.multi = multi;
     },
 
+    get _shouldUpdateSelection() {
+      return this.selected != null ||
+        (this.selectedValues != null && this.selectedValues.length);
+    },
+
     _updateSelected: function() {
       if (this.multi) {
         this._selectMulti(this.selectedValues);