Make export URL restful.

STUD-846

cms/templates/widgets/header.html

@@ -21,6 +21,7 @@
             course_team_url = location.url_reverse('course_team/', '')
             assets_url = location.url_reverse('assets/', '')
             import_url = location.url_reverse('import/', '')
+            export_url = location.url_reverse('export/', '')
       %>
       <h2 class="info-course">
         <span class="sr">${_("Current Course:")}</span>
@@ -95,7 +96,7 @@
                     <a href="${import_url}">${_("Import")}</a>
                   </li>
                   <li class="nav-item nav-course-tools-export">
-                    <a href="${reverse('export_course', kwargs=dict(org=ctx_loc.org, course=ctx_loc.course, name=ctx_loc.name))}">${_("Export")}</a>
+                    <a href="${export_url}">${_("Export")}</a>
                   </li>
                 </ul>
               </div>