Apparently, if a http git remote is on a local network address,
uuid discovery fails. The error message does not mention that 
annex.security.allowed-ip-addresses has to be set, but setting it solves
the problem. 

There needs to be a better error message, or possibly don't apply
annex.security.allowed-ip-addresses to uuid discovery -- which does not
seem like it would involve the kind of security problem that config exists
to prevent. --[[Joey]]

> While I think it would be safe to bypass
> annex.security.allowed-ip-addresses in this case, it seemed complicated
> to implement that, and also getting that wrong would be a security hole.
> Since this is a pretty unusual case, I think it's ok to need that to be
> set.
> 
> So, I've improved the error message in this case. (And a few other
> cases.) [[done]] --[[Joey]]
