Update drn_train.py

fix some bug about train DRN model

tutorials/train/image_restoration/drn_train.py

@@ -5,8 +5,6 @@ sys.path.append(os.path.abspath('../PaddleRS'))
 import paddle
 import paddlers as pdrs
 
-if __name__ == "__main__":
-
 # 定义训练和验证时的transforms
 train_transforms = pdrs.datasets.ComposeTrans(
     input_keys=['lq', 'gt'],
@@ -78,4 +76,5 @@ if __name__ == "__main__":
     output_dir='output_dir',
     validate=5000,
     snapshot=5000,
-        lr_rate=0.0001)
+    lr_rate=0.0001,
+    log=10)