hugofs: Fix glob case-sensitivity bug

hugofs: Fix glob case-sensitivity bug

On Linux, `hugofs.Glob` does not hit any directories which includes
uppercase letters. (This does not happen on macOS.)

Since `resources.GetMatch/Match` uses `Glob`,

```
{{ resources.GetMatch "Foo/bar.css" }}
```

this does not match `assets/Foo/bar.css` .

On the other hand, you can get it with

```
{{ resources.Get "Foo/bar.css" }}
```