Fix two issues with chaining ECS enabled queries

Fix two issues with chaining ECS enabled queries

1. The main index does not sort on subnet, so we cannot assume any ordering in the
birthday compare used for chains.
2. The lookup key is overwritten by the matched key from the waiters, meaning
that we cannot use it to pass values. This means we have to
recompute the ECS info in the incoming path for each chain member.

Signed-off-by: Otto Moerbeek <otto.moerbeek@open-xchange.com>