Comment 3 for bug 1728365

DpkgTerminalLog.txt contains this snippet near the end:

dpkg: considering removing systemd-shim in favour of systemd-sysv ...
dpkg: systemd-shim is not properly installed; ignoring any dependencies on it
dpkg: yes, will remove systemd-shim in favour of systemd-sysv
Preparing to unpack .../systemd-sysv_232-21ubuntu7.1_amd64.deb ...
Unpacking systemd-sysv (232-21ubuntu7.1) over (229-4ubuntu20) ...
Removing 'diversion of /usr/share/dbus-1/system-services/org.freedesktop.systemd1.service to /usr/share/dbus-1/system-services/org.freedesktop.systemd1.service.systemd by systemd-shim'
dpkg-divert: error: rename involves overwriting '/usr/share/dbus-1/system-services/org.freedesktop.systemd1.service' with
  different file '/usr/share/dbus-1/system-services/org.freedesktop.systemd1.service.systemd', not allowed
dpkg: error processing archive /var/cache/apt/archives/systemd-sysv_232-21ubuntu7.1_amd64.deb (--unpack):
 subprocess installed post-removal script returned error exit status 2