Cease using ci-puppetmaster.openstack.org

Now that the migration to puppetmaster.openstack.org is complete,
remove duplicate references to ci-puppetmaster.openstack.org and
also take out the temporary Puppet v2 vs v3 compatibility code used
to choose between them.

Change-Id: I32d48e844ab1872391f9f2a4e233804b7a29feb5
Merge "Cease using ci-puppetmaster.openstack.org"