The `git commit --fixup` command unwraps wrapped onelines when
constructing the commit message, without wrapping the result.
We need to make sure that `git rebase --autosquash` keeps handling such
cases correctly, in particular since we are about to move the autosquash
handling into the rebase--helper.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>