Outdated comments around HandleFunctionRequest

Hi,

PostgresMain() has the following blurb for fastpath functions:

				/*
				 * Note: we may at this point be inside an aborted
				 * transaction.  We can't throw error for that until we've
				 * finished reading the function-call message, so
				 * HandleFunctionRequest() must check for it after doing so.
				 * Be careful not to do anything that assumes we're inside a
				 * valid transaction here.
				 */
and in HandleFunctionRequest() there's:

 * INPUT:
 *		In protocol version 3, postgres.c has already read the message body
 *		and will pass it in msgBuf.
 *		In old protocol, the passed msgBuf is empty and we must read the
 *		message here.

which is not true anymore.  Followed by:

	/*
	 * Now that we've eaten the input message, check to see if we actually
	 * want to do the function call or not.  It's now safe to ereport(); we
	 * won't lose sync with the frontend.
	 */

which is also not really meaningful, because there's no previous code in
the function.

This largely seems to be damage from


commit 2b3a8b20c2da9f39ffecae25ab7c66974fbc0d3b
Author: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date:   2015-02-02 17:08:45 +0200

    Be more careful to not lose sync in the FE/BE protocol.

Heikki?


- Andres