add a hack allowing specific cid for event creation
    
    To do event creation 'correctly' we need to wait for the compose
    to be in PDC (so we can find its kojipkgs location from its
    label by querying PDC for the compose ID), or we need to only
    create events for 'production' composes that have been synced
    somewhere we can find them from the label. At present neither
    of these is possible, so we need a cheat. This lets us specify
    the compose ID (hence the kojipkgs location) for a compose when
    creating it, for the purpose of creating the download table.
    
    For finding the compose for the event subsequently, we're just
    going to have to cross our fingers and assume it's been added
    to PDC by the time we need to do that.
    
    This also drops the now-unnecessary variant ff_release for
    NightlyEvent (fedfind now handles this fudge, so we don't need
    it in wikitcms) and drops an unused test file just because I
    suck at git commits.