We cannot just leave that to the `-port` parameter since that only
controls the container internal port weave is listening on (and uses
as the default destination port for outbound connections). Also, we
need the port for connection tracking cleanup during `stop` and
`reset`.
So we make setting `WEAVE_PORT` the only documented mechanism for
overriding the port, and let `-port` set the container internal port
only (and the script pays attentiont to that, so it can establish the
correct port mapping).
Matthias Radestock
272e63643c