Trigger empty event on keepalive timeout (#1466)

js/libtextsecure.js

@@ -38393,6 +38393,9 @@ MessageReceiver.prototype.extend({
         if (ev.code === 3000) {
             return;
         }
+        if (ev.code === 3001) {
+            this.onEmpty();
+        }
         // possible 403 or network issue. Make an request to confirm
         return this.server.getDevices(this.number)
             .then(this.connect.bind(this)) // No HTTP error? Reconnect

libtextsecure/message_receiver.js

@@ -57,6 +57,9 @@ MessageReceiver.prototype.extend({
         if (ev.code === 3000) {
             return;
         }
+        if (ev.code === 3001) {
+            this.onEmpty();
+        }
         // possible 403 or network issue. Make an request to confirm
         return this.server.getDevices(this.number)
             .then(this.connect.bind(this)) // No HTTP error? Reconnect