Remove vestigial client_ready_quark from McdClient
Remove vestigial client_ready_quark from McdClient

This never actually "became ready" unless the client disappeared.

freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control