Use daemon property instead of setDaemon method
Use daemon property instead of setDaemon method

The setDaemon method of the threading.Thread was deprecated
in Python 3.10 (*).
Replace the setDaemon method with the daemon property.

*: https://docs.python.org/3.10/library/threading.html#threading.Thread.setDaemon

Change-Id: Ic854dc3c393d382a8acd20d89f56bff198a2ec5e
Signed-off-by: Takashi Natsume <2c48eb5bf73c355a2d5583bc776dffa383cdf819@gmail.com>

openstack/swift,openstack/swift,openstack/swift,openstack/swift