lofs: remove of a symlink should use lstat

A symlink can be dangling, which means that `stat` will return `ENOENT`.
When removing we want to remove the symlink itself so `lstat` is
appropriate.

Signed-off-by: David Scott <dave.scott@unikernel.com>

unix/lofs9p.ml

@@ -470,7 +470,7 @@ module New(Params : sig val root : string list end) = struct
       let rec loop () =
         Lwt.catch
           (fun () ->
-            Lwt_unix.LargeFile.stat realpath
+            Lwt_unix.LargeFile.lstat realpath
             >>= fun stats ->
             ( if stats.Lwt_unix.LargeFile.st_kind = Lwt_unix.S_DIR
               then Lwt_unix.rmdir else Lwt_unix.unlink ) realpath