$ git clone -n https://src.fedoraproject.org/rpms/libbluray.git /var/lib/mock/f45-build-16032-481/root/chroot_tmpdir/scmroot/libbluray
Cloning into '/var/lib/mock/f45-build-16032-481/root/chroot_tmpdir/scmroot/libbluray'...
$ git fetch origin df457a63d329e4259c18911852476640080da2a4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libbluray
 * [new ref]         df457a63d329e4259c18911852476640080da2a4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at df457a6 Undo version bump and rebuild again