$ git clone -n https://src.fedoraproject.org/rpms/ghc-cryptohash-sha1.git /var/lib/mock/f41-build-839491-160201/root/chroot_tmpdir/scmroot/ghc-cryptohash-sha1
Cloning into '/var/lib/mock/f41-build-839491-160201/root/chroot_tmpdir/scmroot/ghc-cryptohash-sha1'...
$ git fetch origin b8e9c5ef548163585e6bb2d66fa67bf6a6d766ad:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-cryptohash-sha1
 * [new ref]         b8e9c5ef548163585e6bb2d66fa67bf6a6d766ad -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b8e9c5e refresh .cabal revision