Fix cert_request for KDC cert
ca_kdc_check() expects an API object, not an LDAP connection. Issue was
introduced in commit 8f4abf7bc1607fc44f528b8a443b69cb82269e69.
See: https://pagure.io/freeipa/issue/6739
Fixes: https://pagure.io/freeipa/issue/8686
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>