gall: initialize sub-nonce as 1 during upgrade
gall: initialize sub-nonce as 1 during upgrade

This matches the bunt of 1 for the new ship case. A nonce of 0 is
semantically mapped to old-style subscriptions.

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