unescape path on commonlogger

### Problem
`Rack::File` unescape the file path, https://github.com/rack/rack/blob/master/lib/rack/file.rb#L41 , So the middleware that is setting that up is suppose to escape it, for instance on rails https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/middleware/static.rb#L24 .

The problem is, that the logger, doesn't unescape, and end up showing this log:
```
"GET %2Ffavicon.ico HTTP/1.1"
```

### Solution
call unescape before logging it.

[ref rails/rails#11816]
maybe something like this :
```ruby
(Utils.unescape(s = env["PATH_INFO"]) rescue s),
```
Kind of what we do here:
https://github.com/arthurnn/rack/blob/unescape_logger/lib/rack/request.rb#L311

I dont love the `rescue` all, but I guess that what we need in here to ensure the behaviour.