fix redis score str

ad_recommend.py

@@ -322,7 +322,7 @@ def predict_mid_video_res_with_model(now_date, mid, video_id, abtest_param, abte
         )
         return result
 
-    offline_score = user_score + item_score
+    offline_score = float(user_score) + float(item_score)
     online_features = {
         'ctx_apptype': str(app_type),
         'ctx_week': time.strftime('%w', time.localtime()),