fix repository tree can't handle two loading at once (#13348)

Contributed by Vadim Pushtaev.

git-svn-id: http://svn.redmine.org/redmine/trunk@12274 e93f8b46-1217-0410-a6f0-8f06a7374b81

public/javascripts/application.js

@@ -413,7 +413,7 @@ function expandScmEntry(id) {
 }
 
 function scmEntryClick(id, url) {
-    el = $('#'+id);
+    var el = $('#'+id);
     if (el.hasClass('open')) {
         collapseScmEntry(id);
         el.addClass('collapsed');