[CentOS] el7 systemd service:: ensure var/log owner when User is specified

Tue Feb 9 17:21:40 UTC 2021
Adrian Sevcenco <Adrian.Sevcenco at spacescience.ro>

Hi! Does anyone have an idea how can i (in a nice way [1]) to ensure 
ownership/permissions of log directory in /var/log for a unit
that drops privileges to a user (with User=/Group=)

[1] The ugly way being with script in StartPre and sudo in Start
so i want to use User=
I'm aware of LogsDirectory= but is not available on EL7

Thanks a lot!