ignores default value if available

[JuniorNapier]

https://github.com/ErikWittern/swagger-snippet/blob/a97df1b5e87f43a5cda3fcfa06e1ec8b6ef1d97b/swagger-to-har.js#L240

ignores default value if one is provided... should be similar to

https://github.com/ErikWittern/swagger-snippet/blob/a97df1b5e87f43a5cda3fcfa06e1ec8b6ef1d97b/swagger-to-har.js#L186