Added unittest patches for Python 2.6
diff --git a/tests/test_csr.py b/tests/test_csr.py
index 9cc8a8b..7e9dbd5 100644
--- a/tests/test_csr.py
+++ b/tests/test_csr.py
@@ -6,6 +6,9 @@
 import os
 
 from asn1crypto import csr, util
+from ._unittest_compat import patch
+
+patch()
 
 if sys.version_info < (3,):
     byte_cls = str