Support for option SysVStartPriority= has been removed and it is ignored

Issue

While using tab key to automatic complete command, below message outputing.

[root@R74 ~]# systemctl restart 
Display all 371 possibilities? (y or n)

[root@R74 ~]# tailf  /var/log/messages 
Jul  4 14:59:46 R74 systemd: [/usr/lib/systemd/system/firstboot-graphical.service:14] Support for option SysVStartPriority= has been removed and it is ignored
Jul  4 14:59:46 R74 systemd: [/usr/lib/systemd/system/firstboot-graphical.service:14] Support for option SysVStartPriority= has been removed and it is ignored 
^C 
[root@R74 ~]#