Fix hang on terminate when inproc is connected but never bound.

This fixes the hang we get if you connect to an inproc connection but never bind to it, then try to terminate the context.

The simple solution was to just create a temporary socket and do the bind.  Its a bit hacky that I always create a ZMQ_PAIR socket, but we don't seem to check if the socket types are compatible on bind yet, so it works.