Title: #1555: [Backport][ipa-4-5] 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.
To pull the PR as Git branch:
git remote add ghfreeipa https://github.com/freeipa/freeipa
git fetch ghfreeipa pull/1555/head:pr1555
git checkout pr1555