wal : wal.Verify defer close the opened WAL files

wal.Verify() : The opened WAL files are not closed in error cases. Fixed by adding a
defer.

wal/wal.go

@@ -554,6 +554,11 @@ func Verify(lg *zap.Logger, walDir string, snap walpb.Snapshot) error {
 	if err != nil {
 		return err
 	}
+	defer func() {
+		if closer != nil {
+			closer()
+		}
+	}()
 
 	// create a new decoder from the readers on the WAL files
 	decoder := newDecoder(rs...)
@@ -591,10 +596,6 @@ func Verify(lg *zap.Logger, walDir string, snap walpb.Snapshot) error {
 		}
 	}
 
-	if closer != nil {
-		closer()
-	}
-
 	// We do not have to read out all the WAL entries
 	// as the decoder is opened in read mode.
 	if err != io.EOF && err != io.ErrUnexpectedEOF {