set validatorUrl to null by default

Signed-off-by: Matteo Collina <[email protected]>

Author: mcollina

lib/swagger-initializer.js

@@ -25,7 +25,7 @@ function swaggerInitializer (opts) {
         SwaggerUIBundle.plugins.DownloadUrl
       ],
       layout: "StandaloneLayout",
-      validatorUrl: ${serialize(opts.validatorUrl)},
+      validatorUrl: ${serialize(opts.validatorUrl || null)},
     }, config, {
       url: resolveUrl('./json').replace('static/json', 'json'),
       oauth2RedirectUrl: resolveUrl('./oauth2-redirect.html')