Let the "latest" config option be either an int or a bool
    
    This leverages a new koji feature that lets us retrieve the latest N rpms for a
    package in a tag, instead of just the single latest one.  That koji feature has
    been reviewed, merged, released, and deployed to koji.fedoraproject.org.
    
    Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1082830
    
    Signed-off-by: Ralph Bean <rbean@redhat.com>