CONFDB: Fix standalone application domains
When a standalone application domain was configured, for example:
-------------------------------------------------
[sssd]
domains = appdomain
[application/appdomain]
id_provider=ldap
ldap_uri = ldap://dc.ipa.test
ldap_search_base = cn=accounts,dc=ipa,dc=test
ldap_schema = rfc2307bis
sudo_provider = none
ldap_sasl_mech = gssapi
krb5_realm = IPA.TEST
krb5_server = dc.ipa.test
ldap_user_uid_number = telephonenumber
ldap_user_gid_number = mobile
ldap_user_extra_attrs = location:l
-------------------------------------------------
We would, when unrolling the application section into a domain section,
first add a domain stub, equivalent to:
-----------------------------
[domain/appdomain]
domain_type = application
-----------------------------
Which in config.ldb also contains cn. Then, whem we would add the parameters
from the [application] section, but try to add the cn again.
This didn't happen when inheriting from a POSIX domain, because there we
would set LDB_FLAG_REPLACE for any attributes that exist in the inherited
domain.
This patch skips the cn attribute both when replacing an inherited
domain's attributes and when writing a standalone application domain.
Resolves:
https://pagure.io/SSSD/sssd/issue/3355
Reviewed-by: Pavel Březina <pbrezina@redhat.com>