Limit integration jobs to Puppet5
Limit integration jobs to Puppet5

Because we have so many jobs, it's hard to actually land code. Let's
reduce the gating jobs to just Puppet5 as Puppet 4 is nearing EOL.

This change also moves puppet 6 to experimental if we wish to test it
but does not force puppet 6 on all the jobs. It would be beneficial to
switch the puppet 5 jobs out with puppet 6 jobs next cycle as projects
are migrated to the next version.  TripleO is moving to puppet 5 during
the Stein cycle and tenatively looking to puppet 6 in the Train cycle.

Change-Id: I8ae350a149640badc43abc458c65eb0f93e5fb53

openstack/puppet-openstack-integration,openstack/puppet-openstack-integration,openstack/puppet-openstack-integration