WockyPorter::remote-error: clarify that the error domain is indeed a quark
WockyPorter::remote-error: clarify that the error domain is indeed a quark

As per my review of cosimoc's branches

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