slapos/tests: Refine the assertRegex calling

Python 3.12 completely drops assertRegex.
Also this code keep the Python 2 compatibility.

kedifa/test.py

@@ -38,6 +38,11 @@ import unittest
 import zc.lockfile
 import socket
 import OpenSSL.SSL
+try:
+  from configparser import ConfigParser
+except ImportError:
+  # BBB python2
+  unittest.TestCase.assertRegex = unittest.TestCase.assertRegexpMatches
 
 from cryptography import x509
 from cryptography.hazmat.backends import default_backend
@@ -357,12 +362,12 @@ ez+ONyvetfvjD8cxyQ==
       httplib.CREATED
     )
     location = result.headers.get('Location', '')
-    self.assertRegexpMatches(
+    self.assertRegex(
       location,
       r'^/[a-z0-9]{32}$'
     )
     reserved_reference = result.text
-    self.assertRegexpMatches(
+    self.assertRegex(
       reserved_reference,
       r'^[a-z0-9]{32}$'
     )
@@ -954,7 +959,7 @@ class KedifaIntegrationTest(KedifaCaucaseMixin, unittest.TestCase):
   def test_GET_generateauth(self):
     auth = self.generateauth()
 
-    self.assertRegexpMatches(
+    self.assertRegex(
       auth,
       r'^[a-z0-9]{32}$'
     )
@@ -999,7 +1004,7 @@ class KedifaIntegrationTest(KedifaCaucaseMixin, unittest.TestCase):
       '',
       result.text
     )
-    self.assertRegexpMatches(
+    self.assertRegex(
       result.headers.get('Location', ''),
       r'^/%s/\d+$' % key
     )