caveman count crashes with "corrupted size vs. prev_size" when ignore_regions_file is compressed

When the `IGNORE` path in the Caveman config file points to a compressed file, `caveman count` crashes with the following error message:

```
corrupted size vs. prev_size
Abort
```

I believe this specific instance of the bug is caused by how this function call handles the `ignore_regions_file` read: https://github.com/cancerit/CaVEMan/blob/dev/src/split.c#L218