Remove unused NSE library requires

for lib in nselib/*.lua*; do l=${lib#*/}; l=${l%.lua*}; find . -name \
  \*.lua -o -name \*.nse | xargs grep -l "require .$l\>" | xargs grep \
  -c "\<$l\." | grep ':0$' | awk -F: '{print "'$l'", $1}'; done

Did not remove calls to stdnse.silent_require since these can be used to
abort script execution if OpenSSL is not included, even if the script
does not directly call openssl.* (perhaps it uses comm.tryssl instead,
for instance).

Also did not remove require "strict", since that library is special and
modifies the environment.

scripts/rpc-grind.nse

@@ -1,7 +1,6 @@
 local stdnse = require "stdnse"
 local nmap = require "nmap"
 local rpc = require "rpc"
-local datafiles = require "datafiles"
 local bin = require "bin"
 local math = require "math"
 local io = require "io"