restore showing newsletter error icons as red in angular

![screenshot 2014-07-31 21 45 11](https://cloud.githubusercontent.com/assets/1080613/3774248/e92fc5ca-1925-11e4-82de-becbb8f1fde7.png)

You can combine these two lines with
```
<i class="fa fa-envelope" ng-class="{'icon-error-red': hasSendNewsletterError()}" title="{{contact.send_newsletter}}" ng-show="contact.send_newsletter"></i>
```

You also don't need the brackets on ng-show variables, only for non-ng attributes.