Fix OS versions in metadata
Fix OS versions in metadata

Add Ubuntu 18.04 to metadata file

Change-Id: I6701a3aec14142ab2c75a1ded7b9a3378a215ece

openstack/puppet-neutron,CiscoSystems/puppet-neutron,CiscoSystems/puppet-neutron,CiscoSystems/puppet-neutron,openstack/puppet-neutron