Fix compile warning

This PR fixes a compilation warning that was introduced by https://github.com/openlayers/ol3/commit/c4d6e04e4beab5f6cabdba265f233a012402fba1. 

The warning is:

```
ERR! compile externs/oli.js:152: WARNING - parameter mapBrowserEvent does not appear in oli.interaction.Interaction.prototype.handleMapBrowserEvent's parameter list
```