porter: fix reference to porter error
porter: fix reference to porter error

Signed-off-by: Jonny Lamb <3d1fb3642aaab2ff70e3392a5ab916bf99eed6a3@collabora.co.uk>

noonien-d/wocky,freedesktop-unofficial-mirror/wocky,noonien-d/wocky,noonien-d/wocky,freedesktop-unofficial-mirror/wocky,freedesktop-unofficial-mirror/wocky