fix clusterUUID doc
fix clusterUUID doc

Reason and code suggest that connection *is* closed if a mismatching
clusterUUID is found on a request.

dankenigsberg/logcabin,logcabin/logcabin,logcabin/logcabin,dankenigsberg/logcabin,dankenigsberg/logcabin,TigerZhang/logcabin,TigerZhang/logcabin,TigerZhang/logcabin,TigerZhang/logcabin,dankenigsberg/logcabin,logcabin/logcabin,logcabin/logcabin