Import ABCs from collections.abc
Import ABCs from collections.abc

From the deprecation warning message:
"Using or importing the ABCs from 'collections' instead of from
'collections.abc' is deprecated since Python 3.3, and in 3.9 it
will stop working"

Change-Id: I53b11ebe81977d13a460cdf167ba37c5d3e1bdcd
Closes-Bug: #1856882

openstack/oslo.versionedobjects