Stalls at 99 % sometimes

Sometimes nzbcheck v1.2 stalls at 99 %

```
$ ./nzbCheck.AppImage --progress -h test.com -P 21 -u USER -p PASS -n 20 -i test.nzb
test.nzb has 27789 articles
Using 20 Connections
[=================================================>] 99 % (27785 / 27789) missing: 0
```

This happens mostly when I run a for loop with bash to check all the NZB in a folder.