rgmanager: Status check tuning/optimization
    
    * Don't bother with status checks on 'service'
    abstract resource.
    * Spread status checks out based on completion
    time instead of initiation time.
    * Allow administrators to cap simultaneous
    status checks to prevent load spikes.
    * rhbz487598
    
    Signed-off-by: Lon Hohberger <lhh@redhat.com>