$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-incoming-9514-28253/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-incoming-9514-28253/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin d8518800c05a7d5529bd69b094ec5c55daf0ef48:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         d8518800c05a7d5529bd69b094ec5c55daf0ef48 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d851880 Add an optimization for VHD export from QCOW2 VDIs