Remove sapling_fbclone cargo setup

Summary:
Autocargo should only be used where necessary for some business need
(like OSS).

See https://fb.workplace.com/groups/rust.language/posts/25399030776385531

`fbclone` is not synced to github. The rust version is only built for
Windows and that's done with buck:

https://www.internalfb.com/code/fbsource/[7607fe9950ff]/fbcode/eden/scm/fb/packaging/build_nupkg.py?lines=548-550

The `setup.py` reference looks like leftover from when `fbclone` was
switched to building with buck (D50704305) from cargo (D28299741).

Reviewed By: sggutier

Differential Revision: D51674043

fbshipit-source-id: 0cedd4db2132bbcf39cbf820a898a4e12fa24444

eden/scm/setup.py

@@ -1235,10 +1235,6 @@ def build_libraries(self, libraries):
         RustBinary("scm_daemon", manifest="exec/scm_daemon/Cargo.toml"),
     ]
 
-if havefb and iswindows and not skip_other_binaries:
-    rustextbinaries += [RustBinary("fbclone", manifest="fb/fbclone/Cargo.toml")]
-
-
 if sys.platform == "cygwin":
     print("WARNING: CYGWIN BUILD NO LONGER OFFICIALLY SUPPORTED")