conn: don't u3z(u3_none)
conn: don't u3z(u3_none)

Empirically this seemed to work before (maybe hind events were never
getting sent?), but `u3a_lose` takes a `u3_noun` so it seems best to
follow the specified API.

urbit/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit,urbit/urbit