zed.d, contrib: fix shellcheck errors in scripts

Not sure why this was not caught by CI; perhaps my shellcheck is new
enough to catch more things.

Signed-off-by: Ivan Shapovalov <intelfx@intelfx.name>

cmd/zed/zed.d/history_event-zfs-list-cacher.sh.in

@@ -21,6 +21,7 @@ zed_check_cmd "${ZFS}" sort diff
 
 # We lock the output file to avoid simultaneous writes.
 # If we run into trouble, log and drop the lock
+# shellcheck disable=SC2329
 abort_alter() {
   zed_log_msg "Error updating zfs-list.cache for ${ZEVENT_POOL}!"
   zed_unlock "${FSLIST}"