Fix c10 tracing (#25869)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25869
The c10 code for tracing was not disabling tracing when calling the op like it should have. This caused really weird errors where we were recording tensors for ops called within a given c10 op implementation, and making tracing fail
Test Plan: Imported from OSS
Differential Revision: D17275748
Pulled By: jamesr66a
fbshipit-source-id: b4e89ae5a954a1f476c9e5b8bf405bdc621f0323
