Dont use custom toObject options on save!!!

Found very critical bug in 3.8.17 after d098ad3820dca4f69691b2f3b62d9fc9cdec924a commit.

Don't use custom toObject options on save (http://mongoosejs.com/docs/api.html#document_Document-toObject --> During save, no custom options are applied to the document before being sent to the database.)