Open Stack

Hi,

Working on zmq driver I've noticed that for now zmq.Context is created 
per socket which is definitely redundant. That was introduced by the change

https://review.openstack.org/#/c/126914/5/oslo/messaging/_drivers/impl_zmq.py

It makes the correct thing reducing the global context variable, but I 
think the context is still should have more global scope than per socket.

IMHO It should be created once per Reactor/Client or even per driver 
instance.

By the way (I didn't check it yet with current implementation of the 
driver) such approach should break the IPC, because such kind of sockets 
should be produced from the same context.

Regards,
Oleksii Zamiatin