acu184926 Fix up incorrect cloudstack metadata

https://cloudstack.apache.org/docs/en-US/Apache_CloudStack/4.0.2/html/Admin_Guide/user-data-and-meta-data.html
The public_ipv4 value for cloudstack is the router ip and no longer
really guaranteed to the be instance public ip, so don't use it
acu184926 Prefer private_ips and public_ips array, as these are filtered

Should only make a difference on cloudstack, where the local_ipv4
address can either be a public or private ip
Merge pull request #500 from rightscale/ivory_14_21_acu184926_cloudstack_metadata_advanced

Ivory 14 21 acu184926 cloudstack metadata advanced