tmpfiles.d configurations generally require write access to some places
that are read-only until ostree-remount runs.
Make sure ostree-remount has run first.
Thanks to Cosimo Cecchi for finding and diagnosing this problem.
https://bugzilla.gnome.org/show_bug.cgi?id=724183
Before=local-fs.target umount.target
# Other early boot units that need to write to /var
Before=systemd-random-seed.service plymouth-read-write.service
+# tmpfiles.d usually needs write access to a few places
+Before=systemd-tmpfiles-setup.service
[Service]
Type=oneshot