PyTorch Hub and autoShape update (#1415)

* PyTorch Hub and autoShape update

* comment x for imgs

* reduce comment

detect.py

@@ -89,7 +89,7 @@ def detect(save_img=False):
             txt_path = str(save_dir / 'labels' / p.stem) + ('_%g' % dataset.frame if dataset.mode == 'video' else '')
             s += '%gx%g ' % img.shape[2:]  # print string
             gn = torch.tensor(im0.shape)[[1, 0, 1, 0]]  # normalization gain whwh
-            if det is not None and len(det):
+            if len(det):
                 # Rescale boxes from img_size to im0 size
                 det[:, :4] = scale_coords(img.shape[2:], det[:, :4], im0.shape).round()