Do not send the room with action

By not sending the room with the action, we prevent its state from being updated by registered views listening for on_room_read

src/components/views/rooms/RoomList.js

@@ -97,9 +97,9 @@ module.exports = React.createClass({
                 }
                 break;
             case 'on_room_read':
-                payload.room.setUnreadNotificationCount('total', 0);
-                payload.room.setUnreadNotificationCount('highlight', 0);
-                // Force an update because this state is too deep to cause an update
+                // Force an update because the notif count state is too deep to cause
+                // an update. This forces the local echo of reading notifs to be
+                // reflected by the RoomTiles.
                 this.forceUpdate();
                 break;
         }