salut_ft_manager_parse_caps: say that FT capa is unknown if there is no capa announced
salut_ft_manager_parse_caps: say that FT capa is unknown if there is no capa announced

freedesktop-unofficial-mirror/telepathy__telepathy-salut,freedesktop-unofficial-mirror/telepathy__telepathy-salut,freedesktop-unofficial-mirror/telepathy__telepathy-salut,freedesktop-unofficial-mirror/telepathy__telepathy-salut