MTA virtual provides craziness

[Bill Nottingham]

Adam Williamson (awilliam at redhat.com) said: 
> We now appear to have *four* virtual provides for mail servers:
> 
> MTA
> smtpd
> smtpdaemon
> server(smtp)

smtpdaemon's the oldest one, dating back to at least 1997, so should be
standard. smtpd and MTA came along in 2000 when postfix and exim were
imported into powertools, so likely came from Simon Mudd (who did the
original package before it was imported.) So... accident?

server(smtp) was added in 2007 for
https://bugzilla.redhat.com/show_bug.cgi?id=380621, as part of a Fedora
proposed feature/packaging standard. I don't know that this standard
was ever accepted - if it was, we should nuke the rest.

Bill