Default account backend: include directory creation in _commit
Default account backend: include directory creation in _commit

Also check for errors - we can at least give a useful warning.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=35896
Signed-off-by: Simon McVittie <2b470b34502dbf3ba4bcc04ea7e64f4e0e104f33@collabora.co.uk>

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