Merge pull request pytorch#233 from DTennant/patch-1

Fix a typo in optimized_sync_batchnorm_kernel.py

Author: jjsjann123

apex/parallel/optimized_sync_batchnorm_kernel.py

@@ -51,7 +51,7 @@ def forward(ctx, input, weight, bias, running_mean, running_variance, eps, track
             running_variance.data = running_variance.data * (1-momentum) + momentum*r_v_inc
         else:
             mean = running_mean.data
-            inv_std = 1.0 / torch.sqrt(running_var.data + eps)
+            inv_std = 1.0 / torch.sqrt(running_variance.data + eps)
 
         ctx.save_for_backward(input, weight, mean, inv_std)
         ctx.process_group = process_group