Update IPA CA issuer DN upon renewal
When renewing externally-signed CA or when switching from
externally-signed to self-signed CA, the Issuer DN can change.
Update the ipaCaIssuerDn field of the IPA CA entry upon renewal, to
keep it in sync.
Fixes: https://pagure.io/freeipa/issue/7316
Reviewed-By: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Tibor Dudlak <tdudlak@redhat.com>