update darknet53 pretrain link (#2609)

* update darknet53 pretrain link

* update weights path

PaddleCV/PaddleDetection/configs/yolov3_darknet.yml

@@ -8,8 +8,8 @@ log_smooth_window: 20
 save_dir: output
 snapshot_iter: 2000
 metric: COCO
-pretrain_weights: https://paddlemodels.bj.bcebos.com/yolo/darknet53.tar.gz
-weights: https://paddlemodels.bj.bcebos.com/yolo/yolov3.tar.gz
+pretrain_weights: https://paddle-imagenet-models-name.bj.bcebos.com/DarkNet53_pretrained.tar
+weights: output/yolov3_darknet/model_final
 
 YOLOv3:
   backbone: DarkNet

PaddleCV/PaddleDetection/configs/yolov3_mobilenet_v1.yml

@@ -9,7 +9,7 @@ save_dir: output
 snapshot_iter: 2000
 metric: COCO
 pretrain_weights: http://paddle-imagenet-models-name.bj.bcebos.com/MobileNetV1_pretrained.tar
-weights: https://paddlemodels.bj.bcebos.com/yolo/yolo_mobilenet1.0.tar.gz
+weights: output/yolov3_mobilenet_v1/model_final
 
 YOLOv3:
   backbone: MobileNet

PaddleCV/PaddleDetection/configs/yolov3_r34.yml

@@ -9,7 +9,7 @@ save_dir: output
 snapshot_iter: 2000
 metric: COCO
 pretrain_weights: https://paddle-imagenet-models-name.bj.bcebos.com/ResNet34_pretrained.tar
-weights: https://paddlemodels.bj.bcebos.com/yolo/yolo_resnet34.tar.gz
+weights: output/yolov3_r34/model_final
 
 YOLOv3:
   backbone: ResNet