Remove 12.04 and add 16.04 to metadata
Remove 12.04 and add 16.04 to metadata

Change-Id: Iab08f82cd6b9af9646e5bda83289072e1bfe651f

openstack/puppet-ironic,fuel-infra/puppet-ironic,openstack/puppet-ironic,fuel-infra/puppet-ironic,fuel-infra/puppet-ironic,openstack/puppet-ironic