Fixes problem with other urls passed into the function.

When urls are passed into this function, they originate from Rails.
Rails already knows the full path, so the expansion only should happen
on the default project list.

public/javascripts/openproject.js

@@ -54,7 +54,7 @@ window.OpenProject = (function ($) {
       }
 
       if (!url) {
-        url = "/projects/level_list.json";
+        url = this.getFullUrl("/projects/level_list.json");
       }
 
       if (this.projects) {
@@ -63,7 +63,7 @@ window.OpenProject = (function ($) {
       }
 
       jQuery.getJSON(
-        this.getFullUrl(url),
+        url,
         jQuery.proxy(function (data, textStatus, jqXHR) {
           this.projects = augment(this, data.projects);
           this.fetchProjects.apply(this, fetchArgs);