Fix intermittent conversation sort order problem (#1558)

We were inserting based on what was already in the DOM, instead of
using the index from our conversation collection.

FREEBIE

js/views/inbox_view.js

@@ -110,7 +110,7 @@
 
             this.inboxListView.listenTo(inboxCollection,
                     'add change:timestamp change:name change:number',
-                    this.inboxListView.sort);
+                    this.inboxListView.updateLocation);
 
             this.searchView = new Whisper.ConversationSearchView({
                 el    : this.$('.search-results'),