[orca] Remove no-longer-valid import

[Joanmarie Diggs <joanied src gnome org>]

commit 6554eea302d9761c08459f31b3345a8dc05d54cd
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Thu Feb 23 06:21:14 2017 -0500

    Remove no-longer-valid import

 src/orca/scripts/apps/Thunderbird/script.py |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)
---
diff --git a/src/orca/scripts/apps/Thunderbird/script.py b/src/orca/scripts/apps/Thunderbird/script.py
index 456d13f..470cab2 100644
--- a/src/orca/scripts/apps/Thunderbird/script.py
+++ b/src/orca/scripts/apps/Thunderbird/script.py
@@ -37,7 +37,6 @@ import orca.orca_state as orca_state
 import orca.speech as speech
 import orca.scripts.toolkits.Gecko as Gecko
 
-from .speech_generator import SpeechGenerator
 from .spellcheck import SpellCheck
 
 _settingsManager = settings_manager.getManager()
@@ -88,11 +87,6 @@ class Script(Gecko.Script):
                 Script.enableStickyBrowseMode,
                 cmdnames.SET_BROWSE_MODE_STICKY)
 
-    def getSpeechGenerator(self):
-        """Returns the speech generator for this script."""
-
-        return SpeechGenerator(self)
-
     def getSpellCheck(self):
         """Returns the spellcheck support for this script."""