`--resume` training from URL weights fix (#8884)

train.py

@@ -496,8 +496,8 @@ def main(opt, callbacks=Callbacks()):
             d = torch.load(last, map_location='cpu')['opt']
         opt = argparse.Namespace(**d)  # replace
         opt.cfg, opt.weights, opt.resume = '', str(last), True  # reinstate
-        if is_url(opt.data):
-            opt.data = str(opt_data)  # avoid HUB resume auth timeout
+        if is_url(opt_data):
+            opt.data = check_file(opt_data)  # avoid HUB resume auth timeout
     else:
         opt.data, opt.cfg, opt.hyp, opt.weights, opt.project = \
             check_file(opt.data), check_yaml(opt.cfg), check_yaml(opt.hyp), str(opt.weights), str(opt.project)  # checks