Bug#1051938: Resolved with a reboot

[Michel Meyers]

Hello,

As an FYI: I downgraded systemd 253.5-1 but couldn't get it to function 
("Failed to activate service 'org.freedesktop.systemd1'")

I eventually rebooted my system (ended up having to boot of a live 
distro and fix the initramfs images which had all gotten broken during 
the initial upgrade failure) and the problem has disappeared after that. 
apt upgrade re-applied systemd 254.1-3 with no issues.

- Michel