Revert "Tweak to FileSlice"

This reverts commit d7e32c4.

src/transformers/commands/lfs.py

@@ -116,9 +116,9 @@ def read(self, n=-1):
         if self.n_seen >= self.read_limit:
             return b""
         remaining_amount = self.read_limit - self.n_seen
-        n_to_read = remaining_amount if n < 0 else min(n, remaining_amount)
-        self.n_seen += n_to_read
-        return self.f.read(n_to_read)
+        data = self.f.read(remaining_amount if n < 0 else min(n, remaining_amount))
+        self.n_seen += len(data)
+        return data
 
     def __iter__(self):
         yield self.read(n=4*1024*1024)