[9fans] fs auth commands

[Fco.J.Ballesteros <nemo@plan9.escet.urjc.es>]

> W.r.t. the idefs console commands, it occured to me that we
> now have (or already had?) different ways to enable/disable
> things:
>  - separate commands (allow/disallow, like allow in config mode,
>    and in disk/kfscmd), and
>  - flag subcommands (flag authdisable)
> where with the latter the status (enabled/disabled)
> can be observed with 'flag'. Just an observation.

Yes, and I don't like that. Allow/disallow are like the config mode
allow + reboot.

We could perhaps replace the config mode allow with these other
commands, but I'd suggest we do so only if the distributed file server
does the same (I think we don't want two different systems).

Regarding the auth flag, there's a comment that says that it's for
development (in fact the flag was commented out); thus I'd say
we can forget about it.