The test TestInstallWithCA2 and TestInstallWithCA_DNS2 fail in
test_replica0_with_ca_kra_dns_install because they both try to
install a (first instance of) KRA.
This is a known issue, thus marking as xfail.
Related to https://pagure.io/freeipa/issue/7651
Reviewed-By: Christian Heimes <cheimes@redhat.com>