This fixes the bug when a new transport doesn't become primary on the 2nd device because INBOX from
the new transport isn't fully fetched. Now the `Transports` sync message is received from the old
transport, but as it has updated "From", it updates the primary transport correspondingly. NB: I/O
for the new primary transport isn't immediately started however, this needs a separate fix.
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.
