$ git clone -n https://src.fedoraproject.org/rpms/osc.git /var/lib/mock/f45-build-21176-580/root/chroot_tmpdir/scmroot/osc
Cloning into '/var/lib/mock/f45-build-21176-580/root/chroot_tmpdir/scmroot/osc'...
$ git fetch origin f00493d7c5efc4227d536686aa6bfd279d87fcb1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/osc
 * [new ref]         f00493d7c5efc4227d536686aa6bfd279d87fcb1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f00493d Update to 1.27.3, fixes rhbz#2510697