Build virtualbox images headless
diff --git a/ubuntu-14.04/template.json b/ubuntu-14.04/template.json
index 7296c3c..32a28e1 100644
--- a/ubuntu-14.04/template.json
+++ b/ubuntu-14.04/template.json
@@ -132,6 +132,7 @@
       "ssh_port": 22,
       "ssh_wait_timeout": "10000s",
       "shutdown_command": "echo '{{user `password`}}'|sudo -S shutdown -P now",
+      "headless": true,
       "vboxmanage": [
         [ "modifyvm", "{{.Name}}", "--memory", "1024" ],
         [ "modifyvm", "{{.Name}}", "--cpus", "2" ]