Title: #877: SYSDB: Delete linked local user overrides when deleting a user
thank you for the patch. I wonder if the issue can be solved differently by making
`sss_override` more robust?
I'm asking because the override data is currently only stored in the cache and if it
is removed it is lost. If now a cached entry gets removed accidentally on the server or
by a bug on the client and is added later again the override data will be missing.
See the full comment at https://github.com/SSSD/sssd/pull/877#issuecomment-527846738