Move StateFile into Vagrant::Plugin core

lib/vagrant/plugin.rb

@@ -2,5 +2,6 @@ module Vagrant
   module Plugin
     autoload :V1,        "vagrant/plugin/v1"
     autoload :V2,        "vagrant/plugin/v2"
+    autoload :StateFile, "vagrant/plugin/state_file"
   end
 end

lib/vagrant/plugin/state_file.rb

@@ -1,7 +1,7 @@
 require "json"
 
-module VagrantPlugins
+module Vagrant
-  module CommandPlugin
+  module Plugin
     # This is a helper to deal with the plugin state file that Vagrant
     # uses to track what plugins are installed and activated and such.
     class StateFile

plugins/commands/plugin/command/base.rb

@@ -1,3 +1,5 @@
+require "vagrant/plugin/state_file"
+
 module VagrantPlugins
   module CommandPlugin
     module Command
@@ -11,7 +13,7 @@ module VagrantPlugins
         def action(callable, env=nil)
           env = {
             :gem_helper => GemHelper.new(@env.gems_path),
-            :plugin_state_file => StateFile.new(@env.home_path.join("plugins.json"))
+            :plugin_state_file => Vagrant::Plugin::StateFile.new(@env.home_path.join("plugins.json"))
           }.merge(env || {})
 
           @env.action_runner.run(callable, env)

plugins/commands/plugin/plugin.rb

@@ -17,6 +17,5 @@ DESC
 
     autoload :Action, File.expand_path("../action", __FILE__)
     autoload :GemHelper, File.expand_path("../gem_helper", __FILE__)
-    autoload :StateFile, File.expand_path("../state_file", __FILE__)
   end
 end

test/unit/vagrant/plugin/state_file_test.rb

@@ -1,9 +1,9 @@
 require "json"
 require "pathname"
 
-require File.expand_path("../../../../base", __FILE__)
+require File.expand_path("../../../base", __FILE__)
 
-describe VagrantPlugins::CommandPlugin::StateFile do
+describe Vagrant::Plugin::StateFile do
   let(:path) do
     f = Tempfile.new("vagrant")
     p = f.path