fix /etc/rc.d/gssd so that it doesn't run before /usr is mounted

[rmacklem]

Summary

[e-mail] reported that the gssd daemon was not
starting, because /etc/rc.d/gssd was executed before his local
/usr file system was mounted.
He fixed the problem by adding mountcritlocal to the REQUIRED
line.

This fix seems safe and works for a separately mounted /usr file
system on a local disk.
The case of a separately mounted remote /usr file system (such as
NFS) is still broken, but there is no obvious solution for that.
Adding mountcritremote would fix the problem, but it would
cause a POLA violation, because all kerberized NFS mounts
in /etc/fstab would need the "late" option specified to work.

Test Plan

Tested with/without gssd_enable="YES" in /etc/rc.conf.
(The gssd started fine on the system, which does have
a separately mounted /usr from a local disk.)

[0mp]

Seems reasonable. I've not tested it.

I wonder if this one should get a Relnotes: yes, so that users get reminded about it when 13.0 is released.

etc/rc.d/gssd

7 ↗

(On Diff #79495)

I am not sure, but maybe it should be sorted alphabetically? Just an idea.