Fixes #3971 - warning shown when PXE template is edited and has hosts…

… in build mode

app/helpers/provisioning_templates_helper.rb

@@ -67,6 +67,15 @@ def permitted_actions(template)
     end
   end
 
+  def pxe_with_building_hosts?(template)
+    kinds = ["PXELinux", "PXEGrub"]
+    os_ids = template.operatingsystem_ids
+    template.respond_to?(:template_kind) &&
+      template.template_kind.present? &&
+      kinds.include?(template.template_kind.name) &&
+      Host.where(:build => true, :operatingsystem_id => os_ids).any?
+  end
+
   private
 
   def locations_only?

app/views/templates/_form.html.erb

@@ -35,6 +35,11 @@
                                                                              "http://www.theforeman.org/manuals/#{SETTINGS[:version].short}/index.html#4.4.3ProvisioningTemplates", :rel => 'external')).html_safe) %>
       <% end -%>
 
+      <% if pxe_with_building_hosts?(@template) -%>
+        <%= alert :class => 'alert-warning', :header => '',
+                  :text => icon_text("warning-sign", (_("Warning: The template is associated to at least one host in build mode. To apply the change, disable and enable build mode on hosts to update the live templates."))) %>
+      <% end -%>
+
       <div class='form-group'>
         <label class="control-label" for="template"><%= _("Template editor") %></label>
         <div class="navbar navbar-form">