telepathyClient: allow pango markup in presence changes

We were adding pango markup to the message in ContactManager.setPresence,
but weren't correctly marking the message as containing pango markup,
allowing for uglyness such as "User is <i>away</i>." being shown to the
user.

https://bugzilla.gnome.org/show_bug.cgi?id=642209

js/ui/telepathyClient.js

@@ -679,7 +679,7 @@ Notification.prototype = {
             this.update(text, null, { customContent: true });
         else
             this.update(this.source.title, null, { customContent: true });
-        let label = this.addBody(text);
+        let label = this.addBody(text, true);
         label.add_style_class_name('chat-meta-message');
         this._history.unshift({ actor: label, time: (Date.now() / 1000), realMessage: false});
     },