add missing comma (cosmetic)
add missing comma (cosmetic)

freedesktop-unofficial-mirror/openchrome__xf86-video-openchrome,freedesktop-unofficial-mirror/openchrome__xf86-video-openchrome,freedesktop-unofficial-mirror/openchrome__xf86-video-openchrome,freedesktop-unofficial-mirror/openchrome__xf86-video-openchrome