Bug 974867 - [MMS]Auto suggestion for email address r=Julien

https://bugzilla.mozilla.org/show_bug.cgi?id=974867
okay, but you don't need the parens around `Settings.supportEmailRecipient`.
Also, please indent like this:
```javascript
if (Settings.supportEmailRecipient &&
    Utils.isEmailAddress(a) &&
    Utils.isEmailAddress(b)) {
```