Changed 'L' date format for 'nn' and 'nb' to DD-MM-YYYY

Correct dateformat for norwegian bokmål and norwegian nynorsk is
DD-MM-YYYY
See:
http://www.xn--sprkrdet-c0ac.no/nb-no/Sprakhjelp/Raad/Spoersmaal_og_svar/#dato
and
http://en.wikipedia.org/wiki/Date_format_by_country