* Write sync status to HDD_LOG/log2ram.log.
- Store sync status directly in the HDD log, to make sure we know
about it if something fails. This won't help if the HDD_LOG
variable is borked, but it'll help with everything else.
- Made sync a function to avoid repeating five lines three times.
- log2ram now requires (cp or rsync) and tee, mount, umount.
* Split sync into syncFromDisk and syncToDisk.
- After restarting, I realized that I had combined both types of sync
into one line, when the syncing failed. This fixes that bug.
* Exclude log2ram.log from rsync so rsync doesn't delete it on sync.
From @datenklause
With Type=oneshot, systemd waits until the start action has completed
before it considers the unit to be active, so dependencies start only
after the start action has succeeded. With Type=simple, dependencies
will start immediately after the start action has been dispatched.