McdAccountStorage: fix altered-one signal
McdAccountStorage: fix altered-one signal

https://bugs.freedesktop.org/show_bug.cgi?id=52231

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