TVB 2599: None Scalar fields should not stored in H5 files
Created by: VinczeRobert
The problem was that None values are put as default values in H5 files, thus if it expects a String and gets None for example, it will set that field to an empty string. HDF5 doesn't have a NULL in its type model. Then, at deserialization, it should be None, but it's an empty string and that's why we got that error.
Solved this problem by simply not storing fields if they are None and then they won't be found in the h5 file at deserializing, so they will be set to default values.