[orca] Fix a traceback which was preventing certain keybindings from binding

[Joanmarie Diggs <joanied src gnome org>]

commit aa9687b115a77330afce5b947b5cddda0c9b626c
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Thu Feb 9 19:31:05 2012 -0500

    Fix a traceback which was preventing certain keybindings from binding

 src/orca/orca_gui_prefs.py |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/src/orca/orca_gui_prefs.py b/src/orca/orca_gui_prefs.py
index 7884e2f..1e4002a 100644
--- a/src/orca/orca_gui_prefs.py
+++ b/src/orca/orca_gui_prefs.py
@@ -2849,7 +2849,10 @@ class OrcaSetupGUI(orca_gtkbuilder.GtkBuilderWrapper):
 
         orca_state.capturingKeys = False
         myiter = treeModel.get_iter_from_string(path)
-        originalBinding = treeModel.get_value(myiter, text)
+        try:
+            originalBinding = treeModel.get_value(myiter, text)
+        except:
+            originalBinding = ''
         modified = (originalBinding != new_text)
 
         try: