Fix a typo in syslog.openlog() arguments

Mailman/Logging/Syslog.py

@@ -37,7 +37,7 @@ class _SyslogLogger(object):
         global _syslog_initialized
         if not _syslog_initialized:
             real_syslog.openlog(
-                identity='mailman',
+                ident='mailman',
                 facility=real_syslog.LOG_MAIL)
             _syslog_initialized = True
         self._priority = real_syslog.LOG_INFO