Fix CMake Dev warning in caffe2/CMakeLists.txt (#34886)
Summary:
If arguments of `ENDIF()` block are non-empty, they should match corresponding `IF()` BLOCK
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34886
Test Plan: CI
Differential Revision: D20494631
Pulled By: malfet
fbshipit-source-id: 5fed86239b4a0cb4b3aedd02c950c1b800199d2d
