feat(测试用例): 修复首次导出xmind报错问题

--bug=1048423 --user=王旭 【测试用例】首次导出用例-导出xmind-导出失败报错 https://www.tapd.cn/55049933/s/1608033

backend/services/case-management/src/main/java/io/metersphere/functional/service/FunctionalCaseXmindService.java

@@ -132,7 +132,7 @@ public class FunctionalCaseXmindService {
             noticeSendService.setLanguage(user.getLanguage());
             FunctionalCaseXmindData xmindData = buildXmindData(ids, request);
             dir = new File(LocalRepositoryDir.getSystemTempDir());
-            if (!dir.exists() && !dir.mkdir()) {
+            if (!dir.exists() && !dir.mkdirs()) {
                 throw new MSException(Translator.get("upload_fail"));
             }
             tmpFile = new File(LocalRepositoryDir.getSystemTempDir() +