fix bug that PDB files do not match with labels
fix bug that PDB files do not match with labels

ktaneishi/deepchem,peastman/deepchem,ktaneishi/deepchem,miaecle/deepchem,deepchem/deepchem,miaecle/deepchem,lilleswing/deepchem,lilleswing/deepchem,deepchem/deepchem,ktaneishi/deepchem,lilleswing/deepchem,miaecle/deepchem,peastman/deepchem