Updated openstack/openstack
Project: openstack/taskflow  ee8eede17169868a17334b8b61fa32f9bf5dc067

When creating daemon threads use the bundled threading_utils

Instead of creating daemon threads using the threads module directly
use our small utility file to create the daemon thread on our behalf
and set the appropriate attributes to ensure it's a daemon thread.

This change replaces the existing locations where we were doing this
manually and uses the threading_utils helper function uniformly instead.

Change-Id: I535cee8a63407f753cf812df53c4f5bc83e0c9ae