TODO item for pg_ctl and server detection

While I am working on pg_ctl, I saw this TODO item:

	Have the postmaster write a random number to a file on startup that
	pg_ctl checks against the contents of a pg_ping response on its initial
	connection (without login)
	
	    This will protect against connecting to an old instance of the
	postmaster in a different or deleted subdirectory. 

	http://archives.postgresql.org/pgsql-bugs/2009-10/msg00110.php
	http://archives.postgresql.org/pgsql-bugs/2009-10/msg00156.php

Based on our new PQPing(), do we ever want to implement this or should I
remove the TODO item?  It seems this would require a server connection,
which is something we didn't want to force pg_ctl -w to do in case
authentication is broken.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +