Merge pull request #2309 from fanminjian/fix/fix_nav_does_not_check_pjax

Fixed issue with nav does not check pjax config from an action.

app/views/layouts/rails_admin/_secondary_navigation.html.haml

@@ -1,6 +1,6 @@
 %ul.nav.navbar-nav.navbar-right.root_links
   - actions(:root).each do |action|
-    %li{class: "#{action.action_name}_root_link"}= link_to wording_for(:menu, action), { action: action.action_name, controller: 'rails_admin/main' }, class: "pjax"
+    %li{class: "#{action.action_name}_root_link"}= link_to wording_for(:menu, action), { action: action.action_name, controller: 'rails_admin/main' }, class: action.pjax? ? "pjax" : ""
   - if main_app_root_path = (main_app.root_path rescue false)
     %li= link_to t('admin.home.name'), main_app_root_path
   - if _current_user