Set oldConfig.fqdn

Without this, the re-configure task unregisters the domain since
it thinks the domain has changed

src/apps.js

@@ -329,6 +329,7 @@ function getAppConfig(app) {
         manifest: app.manifest,
         location: app.location,
         domain: app.domain,
+        fqdn: app.fqdn,
         accessRestriction: app.accessRestriction,
         portBindings: app.portBindings,
         memoryLimit: app.memoryLimit,