Make log2ram shutdown after journald has shutdown

#83 At system shutdown log2ram should wait until journald has shutdown before syncing back to disk, otherwise it will sync an unclosed journal log.

log2ram.service

@@ -17,3 +17,4 @@ RemainAfterExit=yes
 
 [Install]
 WantedBy=sysinit.target
+RequiredBy=systemd-journald.service