Default account backend: when deleting from the keyring, remove from secrets
Default account backend: when deleting from the keyring, remove from secrets

Otherwise we'd just delete it, then (because it's still in secrets)
re-commit it!

Signed-off-by: Simon McVittie <2b470b34502dbf3ba4bcc04ea7e64f4e0e104f33@collabora.co.uk>
Reviewed-by: Jonny Lamb <3d1fb3642aaab2ff70e3392a5ab916bf99eed6a3@collabora.co.uk>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=42088
Cherry-picked-from: 16e4507c5001f6f45158ef3d0b46998fa8c1ca2a

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