Don't load group contacts unnecessarily

There are some cases when we want to initialize a group object without
loading its contacts, such as while processing delivery receipts. We
really only need to load the contacts for a group/convo when we are
rendering it, so let the front end handle those cases (which most of
them do already).

js/models/conversations.js

@@ -41,13 +41,12 @@
         this.on('change:avatar', this.updateAvatarUrl);
         this.on('destroy', this.revokeAvatarUrl);
         this.on('read', this.onReadMessage);
-        this.fetchContacts().then(function() {
-            this.contactCollection.each(function(contact) {
-                textsecure.storage.protocol.on('keychange:' + contact.id, function() {
-                    this.addKeyChange(contact.id);
-                }.bind(this));
+        var members = this.get('members') || [];
+        members.map(function(number) {
+            textsecure.storage.protocol.on('keychange:' + m.id, function() {
+                this.conversation.addKeyChange(m.id);
             }.bind(this));
-        }.bind(this));
+        });
     },
 
     addKeyChange: function(id) {
@@ -324,7 +323,7 @@
             } else {
                 var promises = [];
                 var members = this.get('members') || [];
-                this.contactCollection.reset(
+                this.contactCollection.add(
                     members.map(function(number) {
                         var c = ConversationController.create({
                             id   : number,

js/views/conversation_view.js

@@ -269,12 +269,14 @@
         },
 
         messageDetail: function(e, data) {
-            var view = new Whisper.MessageDetailView({
-                model: data.message,
-                conversation: this.model
+            return this.model.fetchContacts().then(function() {
+              var view = new Whisper.MessageDetailView({
+                  model: data.message,
+                  conversation: this.model
+              });
+              this.listenBack(view);
+              view.render();
             });
-            this.listenBack(view);
-            view.render();
         },
 
         listenBack: function(view) {