fix Checksum function: add missing return value remove unneeded file seeking in checksum calculation
fix Checksum function: add missing return value
remove unneeded file seeking in checksum calculation

HalalUr/Reaping2,abannerth/Reaping2,weanti/Reaping2,HalalUr/Reaping2,MrPepperoni/Reaping2-1,ishtoo/Reaping2,Reaping2/Reaping2,abannerth/Reaping2,MrPepperoni/Reaping2-1,Reaping2/Reaping2,weanti/Reaping2,ishtoo/Reaping2