reactive: replace filter_map with library function

Core provides an implementation of filter_map, which is also correct.
The previous implementation reversed the list.
reactive: add logging calls (dis)connect

In particular log the live ports that the switch has when it connects.
This will be helpful for debugging fast-failover issues in the future.
reactive: low-priority rule to drop unrecognized packets

Rogue ICMP traffic is messing with the experiments. Add a low-priority
rule to drop all packets that preceding flows did not handle.