Do not install python2 or its dev package on Ubuntu Bionic hosts
Do not install python2 or its dev package on Ubuntu Bionic hosts

The CI images are now the 'plain' variants so we do not need python2
to be installed on the host

Change-Id: I0d82c76a35b0512a1366c55e06cde72f6b2ce3bd

openstack/openstack-ansible-lxc_hosts,openstack/openstack-ansible-lxc_hosts