stack/erp5: fix NameError in IOS test

This repairs a NameError introduced in 397726e1 (erp5/neoppod/slapos:
Support for python3 from aurel/zope4 branch., 2022-02-03) that was
causing ERP5-IOS test suite to fail in loop.

stack/erp5/buildout.hash.cfg

@@ -66,7 +66,7 @@ md5sum = 0969fbb25b05c02ef3c2d437b2f4e1a0
 
 [template-run-zelenium]
 filename = run-zelenium-test.py.in
-md5sum = 274365ebbade26558ca4836837e781aa
+md5sum = 38653020296e43f84a93b99cb35aaef6
 
 [template]
 filename = instance.cfg.in

stack/erp5/run-zelenium-test.py.in

@@ -10,6 +10,7 @@ from selenium.webdriver.common.by import By
 from selenium.common.exceptions import TimeoutException
 from selenium.webdriver.support.ui import WebDriverWait
 from selenium.webdriver.support import expected_conditions as EC
+import six
 import time
 from urllib import urlopen
 import json