[#1367] fstree: Add size to file counter

FSTree file counter used by writecache. As writecache has now only one
storage, so it is required to use real object size to get writecache
size more accurate than `count * max_object_size`.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/writecache/storage.go

@@ -30,7 +30,7 @@ func (c *cache) openStore(mod mode.ComponentMode) error {
 		fstree.WithDepth(1),
 		fstree.WithDirNameLen(1),
 		fstree.WithNoSync(c.noSync),
-		fstree.WithFileCounter(&c.objCounters),
+		fstree.WithFileCounter(c.counter),
 	)
 	if err := c.fsTree.Open(mod); err != nil {
 		return fmt.Errorf("could not open FSTree: %w", err)