ringaccount: use ERROR_NEED_MIGRATION if necessary

If a migration launched by the daemon fails when decrypting the
account archive, it's because the password is incorrect. The client
should do the migration itself. So, the daemon should informs this
client with ERROR_NEED_MIGRATION

Change-Id: If4871004bf6e09fedcb957b024f50cb723298001
Reviewed-by: Andreas Traczyk <andreas.traczyk@savoirfairelinux.com>