py3: use absolute_import in test-duplicateoptions.py

tests/test-check-py3-compat.t

@@ -56,7 +56,6 b''
   tests/test-demandimport.py not using absolute_import
   tests/test-demandimport.py requires print_function
   tests/test-doctest.py not using absolute_import
-  tests/test-duplicateoptions.py not using absolute_import
   tests/test-duplicateoptions.py requires print_function
   tests/test-filecache.py not using absolute_import
   tests/test-filecache.py requires print_function

tests/test-duplicateoptions.py

@@ -1,5 +1,10 b''
+from __future__ import absolute_import
 import os
-from mercurial import ui, commands, extensions
+from mercurial import (
+    commands,
+    extensions,
+    ui,
+)
 
 ignore = set(['highlight', 'win32text', 'factotum'])