mount_system service log information is not part of the log file

[schaefi]

If the mount_system service successfully mounts the system the log information written so far gets lost because the location will be overwritten.

The issue is a low priority because the information about the mount_system service is also part of the systemd log information which we append at the end of the DMS log file. However that info is then out of sync with the process log and that's confusing.

So if we can solve this it would be nice, if not it's not a big issue