$ git clone -n https://src.fedoraproject.org/rpms/erlang-fast_tls.git /var/lib/mock/f40-build-1493337-23853/root/chroot_tmpdir/scmroot/erlang-fast_tls
Cloning into '/var/lib/mock/f40-build-1493337-23853/root/chroot_tmpdir/scmroot/erlang-fast_tls'...
$ git fetch origin ca99ab1de779673055903ed235815af0eb36d165:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/erlang-fast_tls
 * [new ref]         ca99ab1de779673055903ed235815af0eb36d165 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ca99ab1 fast_tls ver. 1.1.20