- Fix undefined property error, when block#0 not written (starting a new currency)
- Fix undefined property error, when block#0 not written (starting a new currency)

duniter/duniter,blaurent49/duniter,duniter/duniter,duniter/duniter,blaurent49/duniter,duniter/duniter,blaurent49/duniter,duniter/duniter,blaurent49/duniter,duniter/duniter