rpc: fixed get genesis block
rpc: fixed get genesis block

RomanZacharia/pyethapp,ethereum/pyethapp,ethereum/pyethapp,heikoheiko/pyethapp,kustomzone/pyethapp,vaporry/pyethapp,gsalgado/pyethapp,gsalgado/pyethapp,changwu-tw/pyethapp,d-das/pyethapp,RomanZacharia/pyethapp,changwu-tw/pyethapp