Fix SOAP-80 : setup the _nil value to false when optionnal value

With this fix, deserialize function will setup the _nil value to false
and guarantee us that we can re-create the instance from client to server
and vice-versa. Test setup with the job status use case.
Fix warning about unused parameters in the fixUpDefinitions method.

Comment it untill the fixUpDefinitions method do more fixes and may
require these parameters.
Add import_definition bin into .gitignore file