ansible-pull by default will look for local.yml and $fqdn.yml.
For a small network ( home, small company ), having to put the FQDN
in each file is a bit tedious, so this patch also add the shorthostname
as a 3rd default if the fqdn is not found.
also fix the doc, forgot in last commit
Merge pull request #4484 from mscherer/add_short_hostname

ansible-pull by default will look for local.yml and $fqdn.yml.