Use the name for this attribute that exists on Python3
Use the name for this attribute that exists on Python3

It also exists going back to 2.6.

Change-Id: I8a1e285fa8091acf64bf5f9564d1a79882f9b3fb

openstack-dev/hacking,zancas/hacking,hyakuhei/cleantox,hyakuhei/cleantox,openstack-dev/hacking,zancas/hacking