check-dbus-services: prepend something to systemd-cgls output

Hopefully this will prevent the environment (LAVA? systemd?) from
squashing leading spaces and making the tree hard to read.

Differential Revision: https://phabricator.apertis.org/D376
Reviewed-by: pwith

dbus/check-dbus-services

@@ -247,7 +247,7 @@ else
 fi
 
 echo "---------------------------------------------------------------"
-systemd-cgls --no-pager
+systemd-cgls --no-pager | sed -e 's/^/# /'
 
 exit "$any_failed"