Also check for not supplied mails, when checking if dossier could resolved

The check if all content of a dossier is supplied in subdossier's, when they are any active subdossiers, has not include mails.

![bildschirmfoto 2014-08-20 um 17 48 50](https://cloud.githubusercontent.com/assets/485755/3983714/c21b60fa-2881-11e4-9dbd-f9c9b140630d.png)

@lukasgraf