[gegl] gegl-tile: don't leak n_slices when there's no destroy_notify

[N/A <ell src gnome org>]

commit a17ee109c8271106ab1482dd408e1d17a44239d9
Author: Ell <ell_se yahoo com>
Date:   Fri Jul 21 04:58:00 2017 -0400

    gegl-tile: don't leak n_slices when there's no destroy_notify

 gegl/buffer/gegl-tile.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gegl/buffer/gegl-tile.c b/gegl/buffer/gegl-tile.c
index ed180d9..6b5dbe5 100644
--- a/gegl/buffer/gegl-tile.c
+++ b/gegl/buffer/gegl-tile.c
@@ -89,6 +89,10 @@ void gegl_tile_unref (GeglTile *tile)
                   g_slice_free (gint, tile->n_clones);
                 }
             }
+          else
+            {
+              g_slice_free (gint, tile->n_clones);
+            }
         }
     }