McdRequest: emit succeeded, succeeded-with-channel and failed
McdRequest: emit succeeded, succeeded-with-channel and failed

For now, these signals do nothing. They'll soon supersede completed, and
when McdRequest is exported on D-Bus, they'll be mirrored onto D-Bus too.

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