$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-10302-28871/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-10302-28871/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin e9c1dc66b719adf76bf95822efe4fd4a86c7028a:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         e9c1dc66b719adf76bf95822efe4fd4a86c7028a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e9c1dc6 bump release for test build