sysdb: sanitize the dn on cleanup_dn_filter
When trying to get rid of the "local" provider references in
ldap_id_cleanup tests by switching to "files" provider, it's been
noticed that the linearized dn wasn't coming sanitized, which would make
the test to fail.
While I'm not sure here's the right place to have it fixed, this is the
simplest proposal I could come up with.
Related:
https://pagure.io/SSSD/sssd/issue/3304
Signed-off-by: Fabiano Fidêncio <fidencio@redhat.com>
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
Reviewed-by: Pavel Březina <pbrezina@redhat.com>