下载资源失败，提示“downloadFile:fail getParentFile failed”
如题，CocosCreator 输出的小游戏，有时有的机子会出现下载失败，而资源是确实存在的； 该机子关掉小游戏重试又会恢复正常。 出现错误时的日志： {content=[{"screenWidth":640,"locationEnabled":true,"statusBarHeight":24,"notificationAuthorized":true,"screenTop":0,"pixelRatio":3,"safeArea":{"height":360,"width":640,"bottom":360,"top":0,"left":0,"right":640},"system":"Android 6.0","benchmarkLevel":7,"cameraAuthorized":true,"bluetoothEnabled":false,"deviceOrientation":"landscape","windowWidth":640,"brand":"HUAWEI","fontSizeSetting":16,"version":"7.0.10","screenHeight":360,"locationAuthorized":true,"language":"zh_CN","wifiEnabled":true,"microphoneAuthorized":true,"windowHeight":360,"model":"EVA-AL10","platform":"android","SDKVersion":"2.10.2","devicePixelRatio":3}], level=0, appId=wx1212121212121212}
{content=["readFileSync:fail ERR_PARENT_DIR_NOT_EXISTS"], level=2, appId=wx1212121212121212}
{content=["mkdirSync:fail ERR_OP_FAIL"], level=2, appId=wx1212121212121212}
{content=["writeFileSync:fail no such file or directory, open \"wxfile:\/\/usr\/gamecaches\/cacheList.json\""], level=2, appId=wx1212121212121212}
{content=["Create unpacker %s for %s","0d669730c","c0BAyVxX9JzZy8EjFrc9DU"], level=0, appId=wx1212121212121212}
{content=["Create unpacker %s for %s","0e4bc3b03","0ek66qC1NOQLjgYmi04HvX"], level=0, appId=wx1212121212121212}
{content=["Create unpacker %s for %s","079499991","6dkeWRTOBGXICfYQ7JUBnG"], level=0, appId=wx1212121212121212}
{content=["Create unpacker %s for %s","07ce7530a","14TDKXr2NJ6LjvHPops74o"], level=0, appId=wx1212121212121212}
{content=["Download file failed: https:\/\/myresource.cn\/game\/v1\/res\/import\/79\/79eafaef-b7ef-45d9-9c3f-591dc836fc7a.7dfee.json"], level=2, appId=wx1212121212121212}
{content=["downloadFile:fail getParentFile failed"], level=2, appId=wx1212121212121212}
{content=["Download file failed: https:\/\/myresource.cn\/game\/v1\/res\/import\/0e\/0e4bc3b03.fbb43.json"], level=2, appId=wx1212121212121212}
{content=["downloadFile:fail getParentFile failed"], level=2, appId=wx1212121212121212}
{content=["Error 4916, please go to https:\/\/github.com\/cocos-creator\/engine\/blob\/master\/EngineErrorMap.md#4916 to see details. Arguments: 0ek66qC1NOQLjgYmi04HvX"], level=3, appId=wx1212121212121212}
.....
