Renaming member variables in engine.cpp/h (#21283)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21283
ghimport-source-id: 360a138e420ace3cd4ca6ccbc761c8e68319440d
Differential Revision: D15607428
fbshipit-source-id: f8df6b42796a49c4d68fa8366b6a68d5715f6421
