Address watch: incorrect behavior on edge routers

[kgiusti]

A watched address on an edge router reports incorrect consumer counts.

Problem description:

Three router linear deployment: edgeA - interior - edgeB, tcpListener provisioned on edgeA, tcpConnector provisioned on edgeB, same VAN address (of course). Relies on listener tcp socket lifecycle patch:

https://github.com/kgiusti/skupper-router/tree/ISSUE-120

The tcpListener watches the VAN address via the address watch feature.

Initially the tcpListener is notified of one local consumer (weird, but expected because remote consumers are not visible) corresponding to the remote tcpConnector. This is expected.

Issue a curl request against the listener - this succeeds but as soon as curl disconnects the address watch on the tcpListener updates the local consumer count to zero. Further attempts to connect to the listener are refused.

The problem appears to be in addr_proxy.c where the loss of the curl incoming link removes the corresponding out-link to the interior router. Likely due to the "no longer source" check not being aware that the given address also has an address watch associated with it.