[BUG] Passing a non-existent file as --input-pbo results in that file being created

**Describe the bug**
Running SQFVM.exe with --input-pbo pointed at non-existent file results in file being created by that path

**To Reproduce**
```
sqfvm.exe --input-pbo non-existing.pbo
```
Result:
```
>dir
non-existing.pbo
```

**Expected behavior**
No file being created
