Reload WDS server selection on OS change

app/assets/javascripts/foreman_wds/host_edit_extensions.js

@@ -27,6 +27,10 @@ os_selected = function(element){
     $('#wds_server_select select').prop('disabled', true);
     $('#wds_image_select select').prop('disabled', true);
   } else {
+    if ($('#wds_server_select select').val() !== '') {
+        wds_server_selected($('#wds_server_select select'));
+    }
+
     $('#wds_server_select select').prop('disabled', false);
   }
 };

app/views/wds_servers/_server_select.html.erb

@@ -8,5 +8,5 @@
       disabled: f.object.host.operatingsystem.nil? || f.object.host.operatingsystem.family != 'Windows',
       help_inline: :indicator,
       required: true,
-      onchange: 'wds_server_selected(this);', :'data-url' => wds_server_selected_hosts_path, :'data-type' => controller_name.singularize } %>
+      onchange: 'wds_server_selected(this);', :'data-url' => method_path('wds_server_selected'), :'data-type' => controller_name.singularize } %>
 <% end %>