cdaw cassandra_src all time

cf0f55e578f3f1cfa2f0cc259014aef809456e07 | Author: Jonathan Ellis <jbellis@apache.org>
 | 2011-04-27 15:54:56+00:00

    disallow making schema changes to system keyspace
    patch by jbellis; tested by cdaw for CASSANDRA-2563
    
    git-svn-id: https://svn.apache.org/repos/asf/cassandra/branches/cassandra-0.8@1097157 13f79535-47bb-0310-9956-ffa450edef68