"if failed gid disk then alert" throws syntax error

[Marcus Mülbüsch]

Hello all,

the following tests works well with monit-5.20.0

> check filesystem root_fs with path /dev/sda5
>         if failed uid root then alert
>         if failed gid disk then alert

as "ls -l /dev/sda5" shows (not surprisingly):

> brw-rw---- 1 root disk 8, 5 Aug  3 16:33 /dev/sda5

However, monit-5.22.0 cannot start:

> /usr/local/monit.d/filesytems.monit:18: syntax error 'disk'

I could switch to watching the numeric id of the user group disk, but 
would rather keep all my configs unmodified!

Is there any workaround or fix?

Marcus