Fixed the title attribute for choices on "multiple" widgets.

src/js/select2/selection/multiple.js

@@ -85,7 +85,7 @@ define([
       var $selection = this.selectionContainer();
 
       $selection.append(formatted);
-      $selection.prop('title', selection.title);
+      $selection.prop('title', selection.title || selection.text);
 
       $selection.data('data', selection);