Set the zone if specified in the SOAP request

https://bugzilla.redhat.com/show_bug.cgi?id=1135627

The required zone can be specified in the "parameters" being passed
to CreateAutomationRequest. The attribute name is called miq_zone
@mkanoor Would like to see another "nil zone" test where miq_zone is passed without a value like this: ```miq_zone=|var1...```