weed/storage/erasure_coding: Close() after error handling

weed/storage/erasure_coding/ec_test.go

@@ -43,10 +43,10 @@ func TestEncodingDecoding(t *testing.T) {
 
 func validateFiles(baseFileName string) error {
 	nm, err := readNeedleMap(baseFileName)
-	defer nm.Close()
 	if err != nil {
 		return fmt.Errorf("readNeedleMap: %v", err)
 	}
+	defer nm.Close()
 
 	datFile, err := os.OpenFile(baseFileName+".dat", os.O_RDONLY, 0)
 	if err != nil {