Service cannot listen on dynamically assigned port with Svc ID

[jiceatscion]

ran into this while experimenting with registering the resolver service port==0 (as a way to not occupy the port from the public address).

It appears that a port from the dynamic range is properly assigned by the dispatcher but that the registration of the SVC address fails with Cause=="zero port".

This is because the dynamically assigned port isn't passed to the service registration. The original port 0 is passed instead.

This looks like a bug: there is no obvious benefit to rejecting such a configuration and, for better or for worse. if I fix that, the resolver works just fine.