[Libguestfs] [PATCH libnbd] api: Synchronous connect waits til all connections are connected.

[Richard W.M. Jones]

nbd_connect_unix|tcp had a tricky failure case.  This is a consequence
of allowing callers to mix synchronous and asynchronous calls, with
multi-conn thrown into the mix.

I think the new behaviour proposed here is better.  We could do with a
better way of classifying the state of connections, such as are they
connectING.

Rich.