Updated the Ring discovery code to parse out host names properly

We are using Cassandra 1.2.11, and the ring describe code was not parsing host names properly.  The key.toString() was returning the {hostname}/{ip address}, and then the "/" was being stripped out, leaving you with a hostname containing the hostname and ip address as one string.  This change parses out just the hostname part.  When running, we were always encountering an UnknownHostException.