$ git clone -n https://github.com/xcp-ng-rpms/createrepo_c /var/lib/mock/v8.3-incoming-10688-29239/root/chroot_tmpdir/scmroot/createrepo_c
Cloning into '/var/lib/mock/v8.3-incoming-10688-29239/root/chroot_tmpdir/scmroot/createrepo_c'...
$ git fetch origin 210df92501fe0aaa163e8f5eef233bb0be140858:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/createrepo_c
 * [new ref]         210df92501fe0aaa163e8f5eef233bb0be140858 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 210df92 Merge pull request #1 from xcp-ng-rpms/XS-1557