hugofs: Fix glob case-sensitivity bug

[satotake]

On Linux, hugofs.Glob does not hit any directories which include 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" }}