* 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
7b8b444602