Enforce the timezone name to be fedocal_<standar_name>
    
    Apparently evolution and google calendar ignore the timezone specified at the top of the
    file if they follow some sort of standard.
    For example, if you set a meeting in the timezone 'US/Eastern' the timezone ID is EST and
    evolution ignores the timezone decalaration at the top of the file to replace it by its own.
    With this commits the timezone ID becomes fedocal_EST which google calendar and
    evolution won't know and thus won't ignore.
    
    This fixes https://fedorahosted.org/fedocal/ticket/112