cli: drop legacy `SafeConfigParser`

The old `SafeConfigParser` class has been deprecated since Python 3.2, and was
fully dropped in Python 3.11. See issue
[#45173](https://bugs.python.org/issue45173) on Python's bugtracker.

/cc @xavier_thompson who may ping anyone else if needed

slapos/cli/config.py

@@ -77,7 +77,7 @@ class ConfigCommand(Command):
         if not os.path.exists(cfg_path):
             raise ConfigError('Configuration file does not exist: %s' % cfg_path)
 
-        configp = configparser.SafeConfigParser()
+        configp = configparser.ConfigParser()
         if configp.read(cfg_path) != [cfg_path]:
             # bad permission, etc.
             raise ConfigError('Cannot parse configuration file: %s' % cfg_path)

slapos/tests/test_slapproxy.py

@@ -119,7 +119,7 @@ database_uri = %(rootdir)s/lib/proxy.db
     Set config for slapproxy and start it
     """
     conf = slapos.proxy.ProxyConfig(logger=logging.getLogger())
-    configp = configparser.SafeConfigParser()
+    configp = configparser.ConfigParser()
     configp.read(self.slapos_cfg)
     conf.mergeConfig(ProxyOption(self.proxy_db), configp)
     conf.setConfig()