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 I think it would be better to have the zone method return the zone name instead of modifying the options hash.  Then change this line to do the assignment:
```options[:miq_zone] = zone(options)```