Make switching bcore -> Bitcoin Cash work better
Make switching bcore -> Bitcoin Cash work better

Fixed off-by-one block in the find-uahf fork-block
rollback code.

zander/bitcoinclassic,bitcoinclassic/bitcoinclassic,zander/bitcoinclassic,bitcoinclassic/bitcoinclassic,bitcoinclassic/bitcoinclassic,zander/bitcoinclassic,zander/bitcoinclassic,bitcoinclassic/bitcoinclassic,bitcoinclassic/bitcoinclassic,bitcoinclassic/bitcoinclassic,zander/bitcoinclassic,zander/bitcoinclassic