修改Linux的时区，RedHat 7

[root@ip-172-31-29-22 sysconfig]# timedatectl
      Local time: Tue 2018-01-09 08:01:21 UTC
  Universal time: Tue 2018-01-09 08:01:21 UTC
        RTC time: Tue 2018-01-09 08:01:20
       Time zone: UTC (UTC, +0000)
     NTP enabled: yes
NTP synchronized: yes
 RTC in local TZ: no
      DST active: n/a