logger: shorter syntax

classes/config.php

classes/handler/public.php

classes/logger.php

classes/logger/stdout.php

classes/logger/syslog.php

classes/mailer.php

classes/pref/system.php

classes/prefs.php

classes/rpc.php

classes/rssutils.php

classes/userhelper.php

include/errorhandler.php

update.php