This avoids any possibility of interfering with test syntax (such as
TAP) on stdout. TAP specifically does not parse stderr.
Bug: https://bugzilla.gnome.org/show_bug.cgi?id=725981 Reviewed-by: Colin Walters <walters@verbum.org> Signed-off-by: Simon McVittie <simon.mcvittie@collabora.co.uk>