McdStorage: when acting on one account, only store it in its plugin
McdStorage: when acting on one account, only store it in its plugin

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=27727

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