fix: hash header only
fix: hash header only

karlfloersch/pyethereum,shahankhatch/pyethereum,holiman/pyethereum,pipermerriam/pyethereum,ethereum/pyethereum,harlantwood/pyethereum,vaporry/pyethereum,ddworken/pyethereum,ckeenan/pyethereum,pipermerriam/pyethereum,ethermarket/pyethereum,karlfloersch/pyethereum,ethereum/pyethereum,shahankhatch/pyethereum,inzem77/pyethereum