No link-local IPv6 addresses used for call-me-maybe

[flub]

The DiscoveredEndpoints struct (needs rename, no "endpoint") is responsible for collecting the direct addresses which are sent in a call-me-maybe message. But they do not include link-local IPv6 addresses. This means we will not discover the most direct route on an IPv6 local network. There really is not much downside to including these addresses.