Change ResponseDescription css class for the reactivate transition.

See https://github.com/4teamwork/plonetheme.teamraum/pull/241.

Fixes https://github.com/4teamwork/opengever.core/issues/377.

![bildschirmfoto 2014-07-29 um 11 04 25](https://cloud.githubusercontent.com/assets/485755/3732681/6812b178-16ff-11e4-8b7b-178e484b9c49.png)

@ninfaj