remove old pdc entries in fedora.conf. They are no longer used
    
    Should fix:
    
    WARNING: Config option pdc_url was removed and has no effect; Koji is
    queried instead.
    WARNING: Config option pdc_develop was removed and has no effect; Koji
    is queried instead.
    WARNING: Config option pdc_insecure was removed and has no effect; Koji
    is queried instead.
    
    in rawhide composes.
    
    Signed-off-by: Kevin Fenzi <kevin@scrye.com>