apps: return 404 when get returns null

src/routes/apps.js

@@ -48,7 +48,7 @@ exports = module.exports = {
     load
 };
 
-var apps = require('../apps.js'),
+const apps = require('../apps.js'),
     assert = require('assert'),
     auditSource = require('../auditsource.js'),
     BoxError = require('../boxerror.js'),
@@ -64,6 +64,7 @@ async function load(req, res, next) {
 
     const [error, result] = await safe(apps.get(req.params.id));
     if (error) return next(BoxError.toHttpError(error));
+    if (!result) return next(new HttpError(404, 'App not found'));
 
     req.resource = result;