fix str conversion in salt2-old reader
fix str conversion in salt2-old reader

dannygoldstein/sncosmo,sncosmo/sncosmo,dannygoldstein/sncosmo,kbarbary/sncosmo,sncosmo/sncosmo,kbarbary/sncosmo,dannygoldstein/sncosmo,sncosmo/sncosmo,kbarbary/sncosmo