Do not vendor cookbooks using Berkshelf anymore

Instead, use the Berkshelf support in knife-solo and the
vagrant-berkshelf plugin on Vagrant

cookbooks/postfix/templates/default/maps.erb

@@ -1,8 +0,0 @@
-#
-# This file is generated by Chef.
-# Local changes will be overwritten
-#
-
-<% @map.each do |key, value| -%>
-<%= key %><%= @separator %><%= value %>
-<% end unless @map.nil? -%>