fix fetch bug (#4076)

PaddleCV/image_classification/train.py

@@ -225,16 +225,14 @@ def train(args):
                 return
             train_batch_metrics = exe.run(compiled_train_prog,
                                           feed=batch,
-                                          fetch_list=train_fetch_list
-                                          if pass_id % args.print_step == 0 else
-                                          [])
+                                          fetch_list=train_fetch_list)
             t2 = time.time()
             train_batch_elapse = t2 - t1
             train_batch_time_record.append(train_batch_elapse)
-            if pass_id % args.print_step == 0:
-                train_batch_metrics_avg = np.mean(
-                    np.array(train_batch_metrics), axis=1)
-                train_batch_metrics_record.append(train_batch_metrics_avg)
+
+            train_batch_metrics_avg = np.mean(
+                np.array(train_batch_metrics), axis=1)
+            train_batch_metrics_record.append(train_batch_metrics_avg)
             if trainer_id == 0:
                 print_info("batch", train_batch_metrics_avg, train_batch_elapse,
                            pass_id, train_batch_id, args.print_step)