Use the opensmtpd package as it was updated in guix

Julien LepillerThu Feb 20 16:45:42+0100 2020

20e2957

system-configuration/homes
namelast commitdate
files/Separate home management in more specific modulesSun Jun 09 20:31:52+0200 2019
sybil-home.scmUpdate home configurationThu Jul 25 20:32:45+0200 2019
tyreunom.manifestUpdate home configurationThu Jul 25 20:32:45+0200 2019