git-am with 3-way outputs errors when applying, even though the
3-way will usually be successful. We suppress these errors from
git-apply because they are not "true" errors until the 3-way has been
attempted.
Signed-off-by: NStephen Boyd <bebarino@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>