Allow an fqdn extension to be specified for MaaS purposes

This allows the inventory_hostname to be specified as the shortname, and
a common fqdn to applied. E.g. infra01 with an fqdn of .test.com would
count towards a MaaS entity of infra01.test.com whilst the inventory for
ansible would still see it as "infra01".
Merge pull request #107 from andymcc/maas_fqdn

Allow an fqdn extension to be specified for MaaS purposes