Fix bug in ft_ao when two functions does not have overlap
Fix bug in ft_ao when two functions does not have overlap

gkc1000/pyscf,sunqm/pyscf,sunqm/pyscf,sunqm/pyscf,gkc1000/pyscf,gkc1000/pyscf,sunqm/pyscf,gkc1000/pyscf,gkc1000/pyscf