start_fe.sh 中配置日志模式，官方给的例子有误 #184

sys_log_roll_mode = "TIME-DAY"
audit_log_roll_mode = "TIME-DAY"

        String sysFilePattern = "";
        String sysRollMaxSize = "1000000000"; // default ~= 1PB
        String sysrollMode = Config.sys_log_roll_mode;
        if (sysrollMode.equals("TIME-HOUR")) {
            sysFilePattern = "%d{yyyyMMddHH}";      
        } else if (sysrollMode.equals("TIME-DAY")) {
            sysFilePattern = "%d{yyyyMMdd}";        
        } else if (sysrollMode.startsWith("SIZE-MB-")) {
            sysRollMaxSize = String.valueOf(Integer.parseInt(sysrollMode.replaceAll("SIZE-MB-", "")));
            sysFilePattern = "%i";
            newXmlConfTemplate = newXmlConfTemplate.replaceAll("<TimeBasedTriggeringPolicy /><!--SYSLOG-->", "");
        } else {
            throw new IOException("sys_log_roll_mode config error");
        }