Split up the "could not %s %s... %s" message into "could not revert
%s... %s" and "could not apply %s... %s". This makes it easier for
translators to understand the message.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>