Remove duplicate _uc function (also in common.py).
Remove duplicate _uc function (also in common.py).

antoinearnoud/openfisca-france,SophieIPP/openfisca-france,benjello/openfisca-france,adrienpacifico/openfisca-france,sgmap/openfisca-france,SophieIPP/openfisca-france,benjello/openfisca-france,sgmap/openfisca-france,antoinearnoud/openfisca-france,adrienpacifico/openfisca-france