Kill defaults in nn.yaml. (#26282)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26282
Since this isn't the end-user API anymore, we shouldn't have defaults.
Test Plan: Imported from OSS
Differential Revision: D17397153
Pulled By: gchanan
fbshipit-source-id: d44040bec0ee9c70734a53ebcc10a96f12226a29
