Re: Make mesage at end-of-recovery less scary.

> This v8 is changed in...
>
> - Added tests to 011_crash_recovery.pl
>
> - Fixed a bug that server emits "end-of-wal" messages even if it have
>   emitted an error message for the same LSN.
>
> - Changed XLogReaderValidatePageHeader() so that it recognizes an
>   empty page as end-of-WAL.
>
> - Made pg_waldump conscious of end-of-wal.
>
> While doing the last item, I noticed that pg_waldump shows the wrong
> LSN as the error position.  Concretely it emits the LSN of the last
> sound WAL record as the error position.  I will post a bug-fix patch
> for the issue after confirmation.

I noticed that I added a useless error message "garbage record
header", but it is a kind of invalid record length.  So I removed the
message. That change makes the logic for EOW in ValidXLogRecordHeader
and XLogReaderValidatePageHeader share the same flow.