Removes variable which is assigned but not used (#19194)
Summary:
n was set as self.in_channels, but not used within the scope of the function.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19194
Differential Revision: D14937764
Pulled By: ezyang
fbshipit-source-id: 55cb599109309503fee897f77d798fd454fcc02d
