energy_totals: subcategories do not sum correctly

[lindnemi]

in the energy_totals, e.g., agriculture elec, heat and machinery oil do not sum up to agriculture total. seems to be related to rescale_idees_from_eurostat

might apply to other sectors as well

the correct sum is checked by an assert in the pypsa-ariadne-exporter. until this is fixed i will disabled that assert. please re-enable it when the bug gets fixed