Correct setting and deletion of extrapolated_array when column.is_permanent.
Correct setting and deletion of extrapolated_array when column.is_permanent.

benjello/openfisca-core,openfisca/openfisca-core,openfisca/openfisca-core,benjello/openfisca-core,adrienpacifico/openfisca-core,sgmap/openfisca-core