`vagrant box list` warning uses en.yml

lib/vagrant/command/box.rb

@@ -25,7 +25,7 @@ module Vagrant
       desc "list", "Lists all installed boxes"
       def list
         boxes = Box.all(env).sort
-        return env.ui.warn("There are no installed boxes! Use `vagrant box add` to add some.") if boxes.empty?
+        return env.ui.warn("vagrant.commands.box.no_installed_boxes", :_prefix => false)# if boxes.empty?
         boxes.each { |b| env.ui.info(b) }
       end
     end

templates/locales/en.yml

@@ -10,6 +10,8 @@ en:
       vm_creation_required: VM must be created before running this command. Run `vagrant up` first.
       vm_not_found: A VM by the name of %{name} was not found.
     commands:
+      box:
+        no_installed_boxes: There are no installed boxes! Use `vagrant box add` to add some.
       status:
         output: |-
           Current VM states: