[CentOS] Odd switch of running MTA during update through CR to 7.4.1708

Ok, had a real oddity here, and am working to track it down.

I've done a few updates to 7(1708) via CR at this point, and hadn't had 
any real issues, so during a slack time today updated our email server.  
Now, prior to the update, I had our email server set up with postfix, 
but after the update the system had sendmail enabled and postfix 
disabled.  Like I said, I'm still looking into it, but just a heads-up.

A 'systemctl disable sendmail; systemctl stop sendmail' then 'systemctl 
enabled postfix; systemctl start postfix' seems to have restored 
things.  I would probably be well-off to remove sendmail altogether, but 
I would have thought that the startup settings would have been honored 
anyway.

-- 
Lamar Owen
Chief Technology Officer
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC  28772
828-862-5554
www.pari.edu