[distcc] Do not allow localhost compile

[Jean Delvare]

[Michael Donohue]
> It would be nice if this were configurable, so that users can decide
> how many retries they want to have until distcc falls back on the
> localhost.

Actually I wanted to mention that possibility in my previous post, but
for some reason forgot to do so. Question is, is this really needed or
not?

> One advantage to this approach is that the existing behavior can be
> made the default value, remote-attempts=1, but users who do not want
> any local compilation can set a very high remote attempts value, to
> prevent falling back on the localhost, unless there is some massive
> network failure.

After some more thinking, I can't see how it would make a difference. If
I read the code properly, we end up defaulting to localhost anyway if
the list of available remote hosts end up being empty, and that will
happen if all hosts fail. If there is a network failure and all hosts
are unreachable, they will end up being all (temporarily) blacklisted.
Whether they are as the result of the same compilation failing many
times (that will happen with my patch if we don't set a retry limit), or
as the result of several compilations failing once (that will happen
otherwise) doesn't seem to change anything, unless I am mising
something.

NB: Michael, could you please use an e-mail client which doesn't break
the threads?

Thanks,
-- 
Jean Delvare