* Fix logic in os_nova_host_aggregate module
Fix logic around adding availability zone to metadata and comparing existing host list to parameter host list.
Previously, when no availability zone was defined, an empty availability zone was being appended to metadata. This was causing 'empty named availability zone' errors when running the module against an already existing host aggregate with no availability zone. This was fixed by only appending availability zone to metadata if it is not an empty parameter.
Also added set() casting when comparing existing and new host lists. Previously, if existing host list was not in the same order as the host list in the .yml parameter file the module would consider this a change even if the two lists had the same entries.
* Update os_nova_host_aggregate.py
Changes to the metadata format were approved here:
https://github.com/ansible/proposals/issues/54
* Update documentation to the new metadata format
* Changes to metadata-tool to account for new metadata
* Add GPL license header
* Add upgrade subcommand to upgrade metadata version
* Change default metadata to the new format
* Fix exclusion of non-modules from the metadata report
* Fix ansible-doc for new module metadata
* Exclude metadata version from ansible-doc output
* Fix website docs generation for the new metadata
* Update metadata schema in valiate-modules test
* Update the metadata in all modules to the new version
* Update validate-modules
* Validates ANSIBLE_METADATA
* Ensures imports happen after documentation vars
* Some pep8 cleanup
* Clean up some left over unneeded code
* Update modules for new module guidelines and validate-modules checks
* Update imports for ec2_vpc_route_table and ec2_vpc_nat_gateway