Re: mailwrapper behaviour if mailer.conf can't be opened

Ed Maste:
> Mark, Warner and I discussed this today and we agree with the
> arguments you made. One thing I think we should still do is describe
> the behaviour in mailwrapper(8), indicating that we fall back to the
> default MTA if mailer.conf does not exist.

that seems reasonable; i see this is already merged, but i'll submit
another PR for the manpage update.  (please prod me about that if i
forget!)