fix events registration issues

js/views/app_view.js

@@ -198,10 +198,13 @@
     },
     showDevicePairingDialog() {
       const dialog = new Whisper.DevicePairingDialogView();
+      // remove all listeners for this events is fine since the
+      // only listener is right below.
+      Whisper.events.off('devicePairingRequestReceived');
       Whisper.events.on('devicePairingRequestReceived', pubKey =>
         dialog.requestReceived(pubKey)
       );
-      dialog.on('devicePairingRequestAccepted', (pubKey, cb) =>
+      dialog.once('devicePairingRequestAccepted', (pubKey, cb) =>
         Whisper.events.trigger('devicePairingRequestAccepted', pubKey, cb)
       );
       this.el.append(dialog.el);