made environment file for the service.

I am unable to reproduce systemctl set-environment to work as
advertized.

roles/mariadb/templates/mysql.service

@@ -6,6 +6,7 @@ Requires=docker.service
 [Service]
 TimeoutStartSec=0
 Restart=always
+EnvironmentFile=/srv/mariadb/systemd_environment
 ExecStartPre=-/usr/bin/docker kill %n || /bin/true
 ExecStartPre=-/usr/bin/docker rm %n
 ExecStartPre=/usr/bin/docker pull mariadb:10.2