2.6 Fix html helper regression

The following view code:

```php
$this->Html->css('test.min', array('inline' => false));
$this->Html->script('test.min', array('inline' => false));
```

will not output the `test.min.js` `<script>` tag.

Fix suggested by @AD7six 
These dots could match anything. You can also use `$this->stringContains()` to avoid that issue.