fix(data): read img bug in voc dataset (Megvii-BaseDetection#1615)

fix(data): read img bug in voc dataset

Author: yuangpeng

yolox/data/datasets/voc.py

@@ -189,8 +189,8 @@ def load_image(self, index):
 
         return img
 
-    @cache_read_img
-    def read_img(self, index, use_cache=True):
+    @cache_read_img(use_cache=True)
+    def read_img(self, index):
         return self.load_resized_img(index)
 
     def pull_item(self, index):