keep db post_process param of yml same with utility.py

configs/det/det_db_icdar15_reader.yml

@@ -18,5 +18,4 @@ TestReader:
   infer_img:
   img_set_dir: ./train_data/icdar2015/text_localization/
   label_file_path: ./train_data/icdar2015/text_localization/test_icdar2015_label.txt
-  test_image_shape: [736, 1280]
   do_eval: True

configs/det/det_r18_vd_db_v1.1.yml

@@ -51,7 +51,7 @@ Optimizer:
 PostProcess:
   function: ppocr.postprocess.db_postprocess,DBPostProcess
   thresh: 0.3
-  box_thresh: 0.6
+  box_thresh: 0.5
   max_candidates: 1000
-  unclip_ratio: 1.5
+  unclip_ratio: 1.6