Remove deprecated code

The use of Variable() explicitly is deprecated as Autograd now supports tensors directly.

tutorial-contents/301_regression.py

@@ -17,8 +17,8 @@ x = torch.unsqueeze(torch.linspace(-1, 1, 100), dim=1)  # x data (tensor), shape
 y = x.pow(2) + 0.2*torch.rand(x.size())                 # noisy y data (tensor), shape=(100, 1)
 
 # torch can only train on Variable, so convert them to Variable
-x, y = Variable(x), Variable(y)
-
+#x, y = Variable(x), Variable(y)
+#The above code is depricated. Now,autograd directly supports tensors
 # plt.scatter(x.data.numpy(), y.data.numpy())
 # plt.show()
 
@@ -60,4 +60,4 @@ for t in range(100):
         plt.pause(0.1)
 
 plt.ioff()
-plt.show()
+plt.show()