Mark the "Could not read from '%s'" message that was added to
builtin/merge.c in v1.7.4.2~25^2 (merge: honor prepare-commit-msg
hook) by Jay Soffian for translation.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>