fix clang override path
fix clang override path

Reviewed By: ngorogiannis

Differential Revision: D37753573

fbshipit-source-id: 2be0aefd3245ea9c62b9b99a09e1ed5faf1bedd8

facebook/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer