Table: Fixed feed race condition

Table: Fixed feed race condition

The problem happened like this:

1. Single route for the given net in table
2. A feed is started
3. The route is deleted (from another thread)
4. The feed finds an empty net, exports nothing, ignores journal (here is bug)
5. The route is added
6. The export transitions from FEEDING to READY
7. While processing the journal, the route deletion and addition combines into noop.

This way routes mysteriously disappeared in specific cases of link instability.

Problem fixed by explicitly marking the empty-net journal entries as processed in step 4.