Fixed global assignments with nse_check_globals

All fixes made by hand. A couple real bugs/errors fixed, due to
copy-paste of code from other scripts without changing variable names.

scripts/ip-geolocation-maxmind.nse

@@ -2,6 +2,7 @@ local bit = require "bit"
 local io = require "io"
 local ipOps = require "ipOps"
 local math = require "math"
+local nmap = require "nmap"
 local stdnse = require "stdnse"
 local table = require "table"