Test: use unittest from standard library

test/test_addressbook.py

-from logilab.common.testlib import unittest_main
+import unittest
 from cubicweb.devtools.testlib import AutomaticWebTest
 
 
@@ -14,4 +14,4 @@ class AddressbookAutomaticWebTest(AutomaticWebTest):
 del AutomaticWebTest
 
 if __name__ == '__main__':
-    unittest_main()
+    unittest.main()