Add a require for File in Common

lib/msf/core/post/common.rb

@@ -1,4 +1,7 @@
 # -*- coding: binary -*-
+
+require 'msf/core/post/file'
+
 module Msf
 class Post
 

lib/msf/core/post/file.rb

@@ -1,9 +1,6 @@
 # -*- coding: binary -*-
 
-module Msf
-class Post
-
-module File
+module Msf::Post::File
 
 	def cd(path)
 		if session.type == "meterpreter"
@@ -446,6 +443,3 @@ protected
 		line_max
 	end
 end
-
-end
-end