set zmq channel linger option to 0 (#1450)
set zmq channel linger option to 0 (#1450)

As reported in #1438 , with monitoring enabled, it took 31s for a very short workflow.
This is because we recently changed the monitoring closing mechanism in PR #1403 .
But it took a long time for the Hub process to join because of the long zmq context termination.

This PR sets the zmq lingering option to 0, so the context will terminate immediately.

Fixes #1438
Parsl/parsl,Parsl/parsl,Parsl/parsl,Parsl/parsl