LDAP attribute options aren't enforced in the schema, thus we strip them when checking attribute conformance with the schema. This, however, can leave us with a situation when multiple base LDAP attribute names are present in the list of attribute names to check. Use set of attribute names to deduplicate the list. Fixes: https://pagure.io/freeipa/issue/8328 Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com> Reviewed-By: Christian Heimes <cheimes@redhat.com> Reviewed-By: Rob Crittenden <rcritten@redhat.com>