openqa amqp: fix stg-on-prod queue names
    
    so, this was working before somehow, but it was pretty clearly
    wrong. We were using queues owned by openqa.stg on the prod
    rabbitmq instance for the cases where the openQA "stg" consumers
    need to listen to prod queues. This can only have been working
    with an openqa.stg user on prod, which seems wrong. Instead,
    these three consumers should do it the way the relval and
    relvalami consumers do - use a queue owned by the "openqa" user,
    but with a suffix so they have a different queue from the actual
    prod queue. The upshot of this is that in the configs, we should
    go from:
    
    amqp_url = "amqps://openqa:@rabbitmq.fedoraproject.org/%2Fpubsub"
    ...
    queue = "openqa.stg_scheduler"
    
    - which is weird and I have no idea how it ever worked - to:
    
    amqp_url = "amqps://openqa:@rabbitmq.fedoraproject.org/%2Fpubsub"
    ...
    queue = "openqa_scheduler_stg"
    
    - which seems much more sensible.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>