$ git clone -n https://src.fedoraproject.org/rpms/rtmpdump.git /var/lib/mock/f45-build-34753-691/root/chroot_tmpdir/scmroot/rtmpdump
Cloning into '/var/lib/mock/f45-build-34753-691/root/chroot_tmpdir/scmroot/rtmpdump'...
$ git fetch origin 4d382e199e486cd5b6bc0385cda916bda3b54753:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rtmpdump
 * [new ref]         4d382e199e486cd5b6bc0385cda916bda3b54753 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4d382e1 port to nettle 4.0 API