$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-incoming-10898-29393/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-incoming-10898-29393/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 6589648ab72a97bda7f3f1a9586921b3bf5efa23:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         6589648ab72a97bda7f3f1a9586921b3bf5efa23 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6589648 Merge pull request #122 from xcp-ng-rpms/asv/backport-sparse-vhd-qcow