Only one collapsed menu on non-admin pages

(cherry picked from commit 96ff845120e7a9c83d5d4c30908b283bb9449247)

app/views/layouts/_admin_sidebar_index.html.haml

@@ -1,4 +1,4 @@
-%ul.nav.nav-pills.nav-stacked.mySidebar
+%ul.nav.nav-stacked.nav-pills.mySidebar.collapse.navbar-collapse#side-nav
   .btn-group
     %button{type: 'button', class: 'btn btn-default btn-link dropdown-toggle', 'data-toggle'=>'dropdown'}
       %span.fa.fa-home

app/views/layouts/_navigation.html.haml

@@ -1,7 +1,8 @@
 .navbar.navbar-default.navbar-fixed-top.nav-osem{role: 'navigation'}
   .container
     .navbar-header
-      - if @conference && @conference.short_title.present?
+
+      - if controller.class.name.split("::").first=="Admin"
         %button{ "data-target"=>"#side-nav", "data-toggle"=>"collapse", class: 'navbar-toggle side-nav-btn', type: 'button' }
           %span.sr-only Toggle navigation
           %span.icon-bar