cman: do not propagate old configurations around
    
    Add a check in ccs_config_validate to make sure that the new
    configuration we are about to load in the running cluster is newer
    than the running config.
    
    This avoids unnecessary ccs_sync of a bad config around.
    
    Resolves: rhbz#619680
    
    Signed-off-by: Lon Hohberger <lhh@redhat.com>
    Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>