Lua 5.2 upgrade [1] for NSE.

[1] http://seclists.org/nmap-dev/2012/q2/34

scripts/metasploit-xmlrpc-brute.nse

@@ -1,3 +1,13 @@
+local brute = require "brute"
+local comm = require "comm"
+local creds = require "creds"
+local nmap = require "nmap"
+local shortport = require "shortport"
+local stdnse = require "stdnse"
+local string = require "string"
+
+local openssl = stdnse.silent_require "openssl"
+
 description=[[
 Performs brute force password auditing against a Metasploit RPC server using the XMLRPC protocol.
 ]]
@@ -20,11 +30,6 @@ author = "Vlatko Kosturjak"
 license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
 categories = {"intrusive", "brute"}
 
-require "shortport"
-require "brute"
-require "comm"
-require "stdnse"
-stdnse.silent_require 'openssl'
 
 portrule = shortport.port_or_service(55553, "metasploit-xmlrpc", "tcp")