fix cert-find errors in CA-less deployment
Under some search conditions (in particular, when user is
specified), the CA sub-search of cert-find command throws an error
on CA-less deployments. Do not execute the CA sub-search on CA-less
deployments.
Fixes: https://pagure.io/freeipa/issue/8369
Reviewed-By: Christian Heimes <cheimes@redhat.com>