fix path bug and add some optimization (#3749)

PaddleRec/din/data/data_process.sh

 #! /bin/bash
 
+set -e
 echo "begin download data"
-mkdir raw_data && cd raw_data
+mkdir raw_data
+cd raw_data
 wget -c http://snap.stanford.edu/data/amazon/productGraph/categoryFiles/reviews_Electronics_5.json.gz
 gzip -d reviews_Electronics_5.json.gz
 wget -c http://snap.stanford.edu/data/amazon/productGraph/categoryFiles/meta_Electronics.json.gz
 gzip -d meta_Electronics.json.gz
-echo "download data successful"
+echo "download data successfully"
 
 cd ..
 python convert_pd.py

PaddleRec/din/train.py

@@ -136,7 +136,7 @@ def train():
 
                 if (global_step > 400000 and global_step % PRINT_STEP == 0) or (
                         global_step <= 400000 and global_step % 50000 == 0):
-                    save_dir = os.path.join(args.model_dir, "/global_step_" + str(
+                    save_dir = os.path.join(args.model_dir, "global_step_" + str(
                         global_step))
                     feed_var_name = [
                         "hist_item_seq", "hist_cat_seq", "target_item",