eden: remove EdenWrappedSCM
eden: remove EdenWrappedSCM

Summary:
This is just a plain wrapper that does nothing but forward to the inner SCM. We
don't need this indirection, thus let's remove it.

Reviewed By: chadaustin

Differential Revision: D35434975

fbshipit-source-id: 868b54be9d71346c34bab18cd1b3fd179de6c31b

facebook/watchman,facebook/watchman,facebook/watchman,facebook/watchman,facebook/watchman,facebook/watchman,facebook/watchman,facebook/watchman,facebook/watchman