handle errors while waiting for compose smartly
    
    Summary:
    So the first attempt to use the waiting stuff in production
    failed because, at some point, koji_done got a socket.error
    from the server. Not sure if that was a Koji outage or some
    kind of rate control, but even if it's rate control and we need
    to tweak the wait interval, this seems advisable: we shouldn't
    die the first time we hit any kind of error while waiting, we
    should retry a few times first (with increasingly long delays
    between the retry attempts). I know bare except clauses are BAD,
    but I think it's OK here as we can't really cover every possible
    exception which might get raised in any module during a 'go hit
    a server and do a bunch of stuff' operation, and if the error
    keeps happening we *are* going to raise it eventually.
    
    Test Plan:
    Check I didn't break the 'normal' case, and try causing
    an error to appear somehow (e.g. disconnect from the network or
    hack up the 'client' instantiation in fedfind to use the wrong URL)
    and see if the error handling works as intended.
    
    Reviewers: garretraziel, jskladan
    
    Reviewed By: garretraziel, jskladan
    
    Subscribers: tflink
    
    Differential Revision: https://phab.qadevel.cloud.fedoraproject.org/D532