format_trailer_info(): drop redundant unfold_value()

format_trailer_info(): drop redundant unfold_value()

This is another preparatory refactor to unify the trailer formatters.

In the last patch we made format_trailer_info() use trailer_item objects
instead of the "trailers" string array. This means that the call to
unfold_value() here is redundant because the trailer_item objects are
already unfolded in parse_trailers() which is a dependency of our
caller, format_trailers_from_commit().

Remove the redundant call.

Signed-off-by: Linus Arver <linusa@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>