sftp and wtmp support

[Bob Proulx]

Heikki Orsila wrote:
> My client uses wtmp information to determine past logins though ssh into
> their production environment. It seems sftp does not write into wtmp, and
> thus, it is not possible to list past sftp sessions. To make this happen
> I can see several options:
>
> 1. We write a custom tool to analyze auth.log to determine past sessions.
> This is not useful for ssh community in general.

I am scanning the /var/log/auth.log file for this information.  That's
where the information is logged.

Bob