scripts: Convert to aliased VUIDs in obj tracker

`object_tracker_generator.py` previously referenced retired VUID strings
for aliased commands.

Change-Id: I402e8629e0e1f36f6831208175444465951a300e
diff --git a/scripts/object_tracker_generator.py b/scripts/object_tracker_generator.py
index 335c4ba..9472e6e 100644
--- a/scripts/object_tracker_generator.py
+++ b/scripts/object_tracker_generator.py
@@ -266,7 +266,7 @@
             if alias:
                 alias_string = 'VUID-%s-%s' % (alias, suffix)
                 if alias_string in self.valid_vuids:
-                    vuid = "\"%s\"" % vuid_string
+                    vuid = "\"%s\"" % alias_string
         return vuid
     #
     # Increases indent by 4 spaces and tracks it globally