$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v9.0-u-ydi1-11252-29610/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v9.0-u-ydi1-11252-29610/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 51115e89615a20a05c13908ac2ef3495ea29b6d3:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         51115e89615a20a05c13908ac2ef3495ea29b6d3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 51115e8 bump release for test build