s6-rc do cleanup in "finish", don't append to "run" script

s6-supervise sends signals (e.g. SIGTERM) to the pid of the process
running "run", so how do we know if the ceanup commands are even
getting executed if the shell interpreter that is supposed to do that
got killed already?

pkgs/liminix-tools/services/builder.sh

@@ -11,7 +11,7 @@ test -n "$contents" && for d in $contents; do
     touch $out/${name}/contents.d/$d
 done
 
-for i in timeout-up timeout-down run notification-fd up down consumer-for producer-for pipeline-name restart-on-upgrade; do
+for i in timeout-up timeout-down run notification-fd up down finish consumer-for producer-for pipeline-name restart-on-upgrade; do
     test -n "$(printenv $i)" && (echo "$(printenv $i)" > $out/${name}/$i)
 done