This reproduces the bug when a new transport doesn't become primary on the 2nd device because I/O
isn't restarted when a new transport is added from a sync message, so INBOX from the new transport
isn't fetched.
Fix get_secondary_addrs() which was using
`secondary_addrs` config that is not updated anymore.
Instead of using `secondary_addrs` config,
use the `transports` table which contains all the addresses.
