Fix build with python3
Fix build with python3

dotsdl/PyTables,jack-pappas/PyTables,mohamed-ali/PyTables,jennolsen84/PyTables,tp199911/PyTables,mohamed-ali/PyTables,mohamed-ali/PyTables,joonro/PyTables,tp199911/PyTables,joonro/PyTables,andreabedini/PyTables,gdementen/PyTables,FrancescAlted/PyTables,FrancescAlted/PyTables,PyTables/PyTables,rdhyee/PyTables,PyTables/PyTables,rabernat/PyTables,jack-pappas/PyTables,gdementen/PyTables,andreabedini/PyTables,gdementen/PyTables,avalentino/PyTables,rabernat/PyTables,jennolsen84/PyTables,rdhyee/PyTables,tp199911/PyTables,rdhyee/PyTables,gdementen/PyTables,andreabedini/PyTables,joonro/PyTables,PyTables/PyTables,jennolsen84/PyTables,mohamed-ali/PyTables,tp199911/PyTables,FrancescAlted/PyTables,rabernat/PyTables,dotsdl/PyTables,jack-pappas/PyTables,jack-pappas/PyTables,rabernat/PyTables,avalentino/PyTables,jack-pappas/PyTables,avalentino/PyTables,dotsdl/PyTables,andreabedini/PyTables,rdhyee/PyTables,joonro/PyTables,dotsdl/PyTables,jennolsen84/PyTables