Fix syslog logging on FreeBSD (#407).

Reviewed-on: https://projects.torsion.org/witten/borgmatic/pulls/407

borgmatic/logger.py

@@ -152,6 +152,8 @@ def configure_logging(
             syslog_path = '/dev/log'
         elif os.path.exists('/var/run/syslog'):
             syslog_path = '/var/run/syslog'
+        elif os.path.exists('/var/run/log'):
+            syslog_path = '/var/run/log'
 
     if syslog_path and not interactive_console():
         syslog_handler = logging.handlers.SysLogHandler(address=syslog_path)