unconditionally restart trigger services on liminix-rebuild

We call s6-rc -u -p default to restart/start the base services
on a rebuild, otherwise services that are only in the new
configuration won't come up. However, this stops any service
started by a trigger. So, workaround is to restart the trigger
service and expect it to restart the services it manages if they're
needed

modules/ifwait/ifwait.nix

@@ -9,6 +9,7 @@ let
 in longrun {
   name = "ifwait.${interface.name}";
   buildInputs = [ service ];
+  isTrigger = true;
   run = ''
     ${ifwait}/bin/ifwait -s ${service.name}  $(output ${interface} ifname) ${state}
   '';