Before, passing an empty suds object as an optional parameter value was treated
the same as not passing that parameter's value or passing it None - the value
would not get marshalled into the constructed SOAP request at all.
Now, user can still not have the value marshalled by passing nothing or None,
but passing an empty object will get marshalled as an actual SOAP request XML
element.
This seems correct as passing an empty object and not passing an object are two
distinct use-cases and there are web-services out there (e.g.
`https://ads.google.com/apis/ads/publisher/v201502/LineItemService?wsdl`) that
do differentiate between the two.
Fixes issue filed on BitBucket under:
`https://bitbucket.org/jurko/suds/issues/81/suds-should-support-an-empty-object`
Kudos to Nicholas Chen (nicholaschen at BitBucket) & Mark Saniscalchi
(msaniscalchi at BitBucket) for reporting the issue and preparing the initial
fix.
313185c9b4