Avoid require race with powershell

Author: Tod Beardsley

modules/exploits/windows/local/ms13_005_hwnd_broadcast.rb

@@ -8,6 +8,7 @@
 require 'msf/core'
 require 'rex'
 require 'msf/core/exploit/exe'
+require 'msf/core/exploit/powershell'
 
 class Metasploit3 < Msf::Exploit::Local
 	Rank = ExcellentRanking