$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn2-9012-27911/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn2-9012-27911/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin ab791cf833c73ea08f897f7d4e9f54f8ec5bd1bd:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         ab791cf833c73ea08f897f7d4e9f54f8ec5bd1bd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ab791cf bump release for test build