Add support for Xenial deployments.
* Disable SSL on Ubuntu Xenial deployments.
* Pin puppetlabs-mysql to a recent commit (until they produce a new
tag).
* Disable Ceph on Ubuntu Xenial deployments, neither Hammer or Jewel currently
work out of the box with puppet-ceph on Xenial.
* Disable Horizon on Ubuntu Xenial deployments: not working yet.
* Do not deploy UCA on Xenial, since we currently deploy Mitaka.
* On Xenial, deploy Puppet using distro packaging, not puppetlabs.com.
* Cleanup /etc/default/puppet on Xenial / Puppet4 runs (workaround)
until we figure what is installing this file on Xenial nodepool
image.
All issues are documented here:
See https://etherpad.openstack.org/p/puppet-openstack-xenial
Change-Id: Ifc8c7e241add830c88b84c1f01770e5e15df1653
e5d6e6b6c0