Dead Code: wangle/concurrent/FiberIOExecutor.h
Dead Code: wangle/concurrent/FiberIOExecutor.h

Summary:
[Wangle] Dead Code: `wangle/concurrent/FiberIOExecutor.h`.

It was just a shim around `folly/executurs/FiberIOExecutor.h` but the shim is no longer required.

Reviewed By: Orvid

Differential Revision: D6068750

fbshipit-source-id: 7487cd19cf5c2b16cdeeef5b4baad0a677729536

facebook/wangle,facebook/wangle,facebook/wangle