Monkey patch original current_thread _active in processutils
Monkey patch original current_thread _active in processutils

Monkey patch the original current_thread to use the up-to-date _active
global variable. This solution is based on that documented at:
https://github.com/eventlet/eventlet/issues/592

Change-Id: I0a2c1e0d8a8cad99d68100d25e88e0d3a2eb8f5c
Related-Bug: #1863021

openstack/oslo.concurrency