[orca] Use Gecko's onChildrenChanged callback for Thunderbird; not the default script's

[Joanmarie Diggs <joanied src gnome org>]

commit f23d8eee87970962b34a6bdc507d1d24048a022e
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Sun Nov 22 14:42:55 2015 -0500

    Use Gecko's onChildrenChanged callback for Thunderbird; not the default script's

 src/orca/scripts/apps/Thunderbird/script.py |    5 -----
 1 files changed, 0 insertions(+), 5 deletions(-)
---
diff --git a/src/orca/scripts/apps/Thunderbird/script.py b/src/orca/scripts/apps/Thunderbird/script.py
index 2f5faeb..0f90cfe 100644
--- a/src/orca/scripts/apps/Thunderbird/script.py
+++ b/src/orca/scripts/apps/Thunderbird/script.py
@@ -203,11 +203,6 @@ class Script(Gecko.Script):
 
         Gecko.Script.onCaretMoved(self, event)
 
-    def onChildrenChanged(self, event):
-        """Callback for object:children-changed accessibility events."""
-
-        default.Script.onChildrenChanged(self, event)
-
     def onSelectionChanged(self, event):
         """Callback for object:state-changed:showing accessibility events."""