clean up the shutdown of webapp

dtp-webapp.js

@@ -30,7 +30,7 @@ module.config = {
 module.log = new SiteLog(module, module.config.component);
 
 module.shutdown = async ( ) => {
-  await SitePlatform.shutdown();
+  return await SitePlatform.shutdown();
 };
 
 (async ( ) => {
@@ -50,8 +50,8 @@ module.shutdown = async ( ) => {
   process.once('SIGINT', async ( ) => {
     module.log.info('SIGINT received');
     module.log.info('requesting shutdown...');
-    await module.shutdown();
-    const exitCode = await SitePlatform.shutdown();
+    const exitCode = await module.shutdown();
+
     process.nextTick(( ) => {
       process.exit(exitCode);
     });