fix the bug in dataloader stop running

Author: lzx1413

data/config.py

@@ -1,7 +1,8 @@
 # config.py
 
 # gets home dir cross platform
-
+import cv2
+cv2.setNumThreads(0)  # pytorch issue 1355: possible deadlock in dataloader
 # note: if you used our download scripts, this should be right
 VOCroot = '/home/user/Database/VOCdevkit'  # path to VOCdevkit root dir
 COCOroot = '/home/user/Database/MSCOCO2017'