Add additional NotFound error check for S3/Exists

base/go/storage/s3/s3.go

@@ -25,6 +25,7 @@ import (
 	"go.resf.org/peridot/base/go/storage"
 	"net/url"
 	"os"
+	"strings"
 )
 
 // S3 is an implementation of the Storage interface for S3.
@@ -161,6 +162,9 @@ func (s *S3) Exists(object string) (bool, error) {
 				return false, nil
 			}
 		}
+		if strings.Contains(err.Error(), "NotFound") {
+			return false, nil
+		}
 		return false, err
 	}
 	return true, nil