data: adds ignore_none options into dict_to_dnode

[steweg]

This patch adds new option, which will skip creation of dnodes, when the value in dict is set to None

[samuel-gauthier]

I don't think it is a good idea to ignore DNodes with the None value, because it is how the empty type is represented. Closing.

[steweg]

That's exactly why it is an option and up to caller to say. I do think it is worthy to have, otherwise if you have complex nested dictionary, you need to traverse it by yourself and remove the keys manually before calling this function.

[samuel-gauthier]

I don't agree. It is up to the model to say, not the caller. As I said, by convention in libyang-python, building a dict containing {"a": None} means setting data associated with a leaf "a" of type empty. Having a flag that changes this convention is too misleading.