Use getattr to avoid crash on respin composes
    
    The code that decides whether to apply the openQA 'important'
    tag to a compose after scheduling jobs for it assumed the
    fedfind release object has `type` and `product` attrs, but
    `RespinRelease` instances don't. (I might fix this fedfind
    side too, not sure). This meant we'd crash (*after* scheduling
    jobs, though) when scheduling jobs for respin composes. Fix
    that by using `getattr`.