Quickfix: missing require in post/windows/escalate/getsystem.rb

Resolves:
[-] WARNING! The following modules could not be loaded!
[-]     contrib/metasploit-framework/modules/post/windows/escalate/getsystem.rb: NameError uninitialized constant Msf::Post::Windows

modules/post/windows/escalate/getsystem.rb

@@ -12,6 +12,7 @@
 require 'msf/core'
 require 'rex'
 require 'metasm'
+require 'msf/core/post/windows/priv'
 
 
 class Metasploit3 < Msf::Post