[gimp] app: don't crash on a dangling image_map_tool->active_picker pointer

[Michael Natterer <mitch src gnome org>]

commit 814c47b0b94424e222fa8951e648d359d7c8196a
Author: Michael Natterer <mitch gimp org>
Date:   Thu May 30 23:28:26 2013 +0200

    app: don't crash on a dangling image_map_tool->active_picker pointer
    
    gimp_operation_tool_set_operation(): set it to NULL when destroying
    the previous operation's options_table (if it was non-NULL it was a
    widget from that table).

 app/tools/gimpoperationtool.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/app/tools/gimpoperationtool.c b/app/tools/gimpoperationtool.c
index e334d39..e1ce72d 100644
--- a/app/tools/gimpoperationtool.c
+++ b/app/tools/gimpoperationtool.c
@@ -312,6 +312,8 @@ gimp_operation_tool_set_operation (GimpOperationTool *tool,
     {
       gtk_widget_destroy (tool->options_table);
       tool->options_table = NULL;
+
+      GIMP_IMAGE_MAP_TOOL (tool)->active_picker = NULL;
     }
 
   if (tool->config)