secrets subscriber: make restart-all work

modules/secrets/subscriber.nix

@@ -5,6 +5,7 @@
   s6,
   s6-rc,
   watch-outputs,
+  s6-rc-up-tree
 }:
 {
   watch,
@@ -47,7 +48,7 @@ let
         echo waiting for $dir
         if test -e $dir/notification-fd; then flag="-U"; else flag="-u"; fi
         ${s6}/bin/s6-svwait $flag /run/service/${name} || exit
-        PATH=${s6-rc}/bin:${s6}/bin:$PATH
+        PATH=${s6-rc}/bin:${s6}/bin:${s6-rc-up-tree}/bin:$PATH
         ${watch-outputs}/bin/watch-outputs ${restart-flag} ${name} ${refs}
       '';
     };