Small refactor: remove useless INFO log, and pring valid PAI token error message (#487)

* Small refactor: remove useless INFO log, and pring valid PAI token error message

src/nni_manager/rest_server/restHandler.ts

@@ -52,7 +52,10 @@ class NNIRestHandler {
 
         // tslint:disable-next-line:typedef
         router.use((req: Request, res: Response, next) => {
-            this.log.info(`${req.method}: ${req.url}: body:\n${JSON.stringify(req.body, undefined, 4)}`);
+            // Don't log useless empty body content
+            if(req.body &&  Object.keys(req.body).length > 0) {
+                this.log.info(`${req.method}: ${req.url}: body:\n${JSON.stringify(req.body, undefined, 4)}`);
+            }
             res.header('Access-Control-Allow-Origin', '*');
             res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
             res.header('Access-Control-Allow-Methods', 'PUT,POST,GET,DELETE,OPTIONS');

src/nni_manager/training_service/pai/paiTrainingService.ts

@@ -508,7 +508,7 @@ class PAITrainingService implements TrainingService {
             } else {
                 if(response.statusCode !== 200){
                     this.log.error(`Get PAI token failed: get PAI Rest return code ${response.statusCode}`);
-                    deferred.reject(new Error(`Get PAI token failed, please check paiConfig username or password`));
+                    deferred.reject(new Error(`Get PAI token failed: ${response.body}, please check paiConfig username or password`));
                 }
                 this.paiToken = body.token;
                 this.paiTokenUpdateTime = new Date().getTime();