Title: #6014: Make Dogtag return XML for ipa cert-find
Using JSON by default within Dogtag appears to cause `ipa cert-find` to
return JSON, when the request was made with XML. We can request that XML
is returned as before by specifying so in the request header.
To pull the PR as Git branch:
git remote add ghfreeipa https://github.com/freeipa/freeipa
git fetch ghfreeipa pull/6014/head:pr6014
git checkout pr6014