python-openstackclient-2.6.1 has been changed
to use osc-lib ClientManager which removes
some private attributes.
We can change '_interface' and '_region_name'
once the requirements change to 2.6.1.
Change-Id: I17fbe2250fdeb60ffb9b2f94df26d9edef00bea6
Closes-Bug: #1605876