[byzanz] Fix segfault when cancelling "Select Area"

[Benjamin Otte <otte src gnome org>]

commit 0860017ebabf1c462568063f01a0139efc20f90a
Author: Benjamin Otte <otte gnome org>
Date:   Fri Aug 28 15:43:47 2009 +0200

    Fix segfault when cancelling "Select Area"

 src/byzanzselect.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/byzanzselect.c b/src/byzanzselect.c
index ecb15b6..1bc5ef6 100644
--- a/src/byzanzselect.c
+++ b/src/byzanzselect.c
@@ -252,7 +252,8 @@ byzanz_select_area (GdkRectangle *rect)
   if (data->root)
     cairo_surface_destroy (data->root);
   g_free (data);
-  g_object_ref (ret);
+  if (ret)
+    g_object_ref (ret);
   return ret;
 }