Make the core git-am messages that use say() translatable. These are
visible on almost every git am invocation.
There are tests that depend on the "Applying" output that need to be
changed to use the test_i18* functions along with this translation.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>