Ensure pinentry-gtk2 is absent.

This will allow to purge a lot of X and GTK dependencies we don't need.

manifests/base.pp

@@ -33,6 +33,8 @@ class tails::base () {
 
   ensure_packages($base_packages)
 
+  package { 'pinentry-gtk2': ensure => absent }
+
   case $::virtual {
     physical: {
       include smartmontools