Re: [9front] plumber: remove $plumbsrv, add optional srvname, usage check

[qwx@sciops.net]

> My point is that with the -m flag you might not need to post the
> srv file to start with and the plumber process would go away
> together with the namespace.
[...]
> The option I implied is only posting the srv file when requested
> whence you wouldn't need to clean it up afterwards in the usual
> case.

Yeah, I see what you mean.  Right now, the plumber doesn't have an
option not to post a srv file, and I'm not sure -m will work nicely
because libplumb relies on it being mounted there.

It makes sense that $plumbsrv be ejected, and I don't see anyone
or anything using it;  on the other hand, I'm not sure we can only
optionally post a service file without breaking people's setups.
I think being able to specify another name is enough.  The program
doesn't use postmountsrv(2) or other srv(2) shit, so we'd have to
add more code for an option to disable this or refactor or
something, I don't know.

I propose that we just push the patch as is unless someone sees a
better solution.

Thanks!
qwx