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

https://bugzilla.mozilla.org/show_bug.cgi?id=974867
I'm sorry, I think this test is still useless for now. Unless I'm mistaken it's not related to the changes in thread_ui.js

And we still need tests for what you actually changed in thread_ui.js: the suggestion list behavior, the fact that we display contacts that have emails.