Disallow doesn't apply to defer_javascript

If I use this:

```
ModPagespeedEnableFilters defer_javascript

ModPagespeedDisallow "*/jquery-ui-1.8.2.custom.min.js"
```

The disallow prevents rewriting of the specified javascript but doesn't prevent it from being deferred.

Would be nice to have a way to make defer exceptions for certain scripts in the pagespeed.conf, whether by using disallow or another setting.
