Ensure correct polkit config written for RHEL6

Ensure the correct polkit config is written for RHEL6, or nova-cpu
will fail to start with libvirt permission errors

Change-Id: I871ef4e03157883db15be41222b7338765fbb843
Merge "Ensure correct polkit config written for RHEL6"
Merge branch 'master' of github.com:openstack-dev/devstack