allow updating of 0 supply assets
allow updating of 0 supply assets

check supply is > 0 before asset range verification on assetupdate


Former-commit-id: aae6b810fbad727f6883168e1dae85bef92f36f3
syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2