Fix generating reports if no week given unix_week() cannot handle week being None but does so for year. It just assumes the current year in this case, although this only duplicates the initialisation of year with c_year in this context. week being None gives TypeError: unsupported operand type(s) for -: 'NoneType' and 'int' load_entries() handles the case with no week given, thus call it anyhow. This fix makes it possible to invoke scripts/getan-report with a year given but no week and seeing the expected result (data for a whole year) instead of a traceback.