ksmutil does not send an 'ods-signer update' command when an update to zonelist.xml only covers deleted zones. I suspect it has to do something with the all_flag not being set in the code.
How to reproduce:
1. Start with zonelist with a couple of zones
2. ods-ksmutil setup; ods-control start
3. Remove some zones from the zonelist
4. ods-ksmutil update zonelist
5. ods-signer zones still shows the removed zones.