$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-10258-28832/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-10258-28832/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin c66e579d78e3a86bcb248a9ccf708f8307e5e60b:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         c66e579d78e3a86bcb248a9ccf708f8307e5e60b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c66e579 bump release for test build