[gimp] app: gimp_transform_tool_transform(): don't unref NULL orig_tiles

[Michael Natterer <mitch src gnome org>]

commit 6606d10be107c7b27439379ef5072c1269ceeb0e
Author: Michael Natterer <mitch gimp org>
Date:   Sat Mar 26 18:57:31 2011 +0100

    app: gimp_transform_tool_transform(): don't unref NULL orig_tiles

 app/tools/gimptransformtool.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/app/tools/gimptransformtool.c b/app/tools/gimptransformtool.c
index 599b259..0860de6 100644
--- a/app/tools/gimptransformtool.c
+++ b/app/tools/gimptransformtool.c
@@ -1317,7 +1317,8 @@ gimp_transform_tool_transform (GimpTransformTool *tr_tool,
                                                                   &new_offset_x,
                                                                   &new_offset_y);
 
-  tile_manager_unref (orig_tiles);
+  if (orig_tiles)
+    tile_manager_unref (orig_tiles);
 
   switch (options->type)
     {