ensure key cutoff doesn't go negative
ensure key cutoff doesn't go negative


Former-commit-id: ddd8c8b1ea03ab1b3f30a6ccbb384aac19f23d42
syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin