add main lock around lookupblockindex in netprocessing cleanup
add main lock around lookupblockindex in netprocessing cleanup


Former-commit-id: 8abc634641cb674ea138d6bb2887a6343a3e4b33
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin