title: Unable to connect to Cassandra after upgrade to 3.0.0
body: <p>I've upgraded Cassandra to 3.0.0 some minutes ago through apt-get upgrade (on Ubuntu Linux 14.04 LTS) and after installation and restarting I could connect to my keyspaces using the cqlsh tool and all was ok but when I tried to connect using the DataStax PHP Driver the first time I got "All connections on all I/O threads are busy" but now I get "No hosts available for the control connection". Connection data are the same, so 127.0.0.1 and the default port 9042, I didn't change nothing in configuration. I've tried to downgrade Cassandra to 2.2.3 but after installation it doesn't complete the start sequence. Is this a bug, of Cassandra or of PHP Driver? 
  There are any ways to restore it without lost datas (with 3.0 or lower version)?</p>