reverting port 0 behaviour in portspec

a change was made to protspec that allowed port 0
when we explicitly dissallowed port 0. This change caused
other code that depended on this behaviour to break
make portspec specs not insane

the specs for the portspec_to_portlist method
need a lot of work. this gives us some btter minimum coverage
Land #3478, disallow port 0 for portspec

[Closes #3478]