[pyatspi2] Fix generateKeyboardEvent

[Mike Gorse <mgorse src gnome org>]

commit d8e081fd0753bf5a8db4b3bb4ccc7dc412fc4244
Author: Mike Gorse <mgorse novell com>
Date:   Thu Jan 6 10:48:38 2011 -0600

    Fix generateKeyboardEvent

 pyatspi/registry.py |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/pyatspi/registry.py b/pyatspi/registry.py
index 4d882bc..f00ecb6 100644
--- a/pyatspi/registry.py
+++ b/pyatspi/registry.py
@@ -373,6 +373,8 @@ class Registry(object):
                 """
                 if not self.has_implementations:
                         self._set_default_registry ()
+                if keysym is None:
+                        keysym = ""
                 Atspi.generate_keyboard_event (keycode, keysym, kind)
 
         def generateMouseEvent(self, x, y, name):