[orca] Fix traceback which can occur getting children via relationset

[Joanmarie Diggs <joanied src gnome org>]

commit a1f5456a7bd3c5d64ec88c88821e87d68d8d9ae6
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Fri Apr 17 11:16:37 2015 -0400

    Fix traceback which can occur getting children via relationset

 src/orca/script_utilities.py |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/orca/script_utilities.py b/src/orca/script_utilities.py
index 5b53446..0ad7e42 100644
--- a/src/orca/script_utilities.py
+++ b/src/orca/script_utilities.py
@@ -2564,7 +2564,8 @@ class Utilities:
         pred = lambda r: r.getRelationType() == pyatspi.RELATION_NODE_PARENT_OF
         relations = list(filter(pred, obj.getRelationSet()))
         if relations:
-            result = [r.getTarget(i) for i in range(relations[0].getNTargets())]
+            r = relations[0]
+            result = [r.getTarget(i) for i in range(r.getNTargets())]
 
         return result or [child for child in obj]