Update CloudNightly and DockerNightly classes for new locations
    
    Someone moved these composes into subdirectories without giving
    me any heads-up at all, thanks, whoever that was! Sadly we now
    cannot generate a compose-urls test data set where all the URLs
    are actually correct, as the messages for composes which were
    moved have the pre-move URLs, not the post-move URLs. So we'll
    just stick with the existing compose-urls dataset and include an
    ugly workaround in the test until we can generate a consistent
    set when we have 180 days of *correct* messages, in November if
    releng doesn't fuck up anything else in the mean time.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>