Lua 5.2 upgrade [1] for NSE.

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

scripts/ipidseq.nse

@@ -1,3 +1,10 @@
+local bin = require "bin"
+local math = require "math"
+local nmap = require "nmap"
+local packet = require "packet"
+local stdnse = require "stdnse"
+local table = require "table"
+
 description = [[
 Classifies a host's IP ID sequence (test for susceptibility to idle
 scan).
@@ -28,10 +35,6 @@ license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
 
 categories = {"safe", "discovery"}
 
-require 'bin'
-require 'packet'
-require 'nmap'
-require 'stdnse'
 
 local NUMPROBES = 6