Release systemd version 241-7~deb10u4co5

Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>

debian/changelog

+systemd (241-7~deb10u4co5) apertis; urgency=medium
+
+  * Force the call of systemd-journal-flush before `/var` unmount.
+    The problem with failed `/var` unmount placed on separate partition
+    have a long story: https://github.com/systemd/systemd/issues/867
+    According messages after the fix integrated into upstream -- there are
+    some corner cases which aren't fully fixed by patches adding [relinquish
+    options](https://gitlab.apertis.org/pkg/systemd/-/merge_requests/26)
+    In case of ostree-based images we have a similar issue since `/var` is
+    bind-mounted in initramfs. Systemd is trying to unmount `/var` on
+    shutdown, however `ExecStop=` command from `systemd-journal-flush`
+    service is not executed during shutdown.
+    By adding `PartOf=var.mount` into service file we force the
+    `systemd-journal-flush.service` to be called prior the `/var` unmount.
+    This allow to unlock the bind-mount, since `journald` have a chance to
+    re-link it's journal into `/run` with `journalctl
+    --smart-relinquish-var` call.
+
+ -- Denis Pynkin <denis.pynkin@collabora.com>  Tue, 17 Nov 2020 23:54:02 +0300
+
 systemd (241-7~deb10u4co4) apertis; urgency=medium
 
   * Handle new capabilities gracefully (PR 16424)