$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-9525-28259/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-9525-28259/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin bce7e601d611cebbecf14749fe0a505e2ca2c767:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         bce7e601d611cebbecf14749fe0a505e2ca2c767 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bce7e60 bump release for test build