Fix for explicit null in CSV quote and escape

Author: Dai MIKURUBE

embulk-parser-csv/src/main/java/org/embulk/parser/csv/CsvParserPlugin.java

@@ -485,8 +485,8 @@ static CsvTokenizer.Builder buildCsvTokenizerBuilderForTesting(final PluginTask
     private static CsvTokenizer.Builder buildCsvTokenizerBuilder(final PluginTask task) {
         try {
             final CsvTokenizer.Builder builder = CsvTokenizer.builder(task.getDelimiter());
-            task.getQuoteChar().ifPresent(q -> builder.setQuote(q.getCharacter()));
-            task.getEscapeChar().ifPresent(e -> builder.setEscape(e.getCharacter()));
+            builder.setQuote(task.getQuoteChar().orElse(QuoteCharacter.noQuote()).getCharacter());
+            builder.setEscape(task.getEscapeChar().orElse(EscapeCharacter.noEscape()).getCharacter());
             builder.setNewline(task.getNewline().getString());
             if (task.getTrimIfNotQuoted()) {
                 builder.enableTrimIfNotQuoted();