Clean up the cassandra driver configuration
Clean up the cassandra driver configuration

- Our previous policies were actually not used at all. They are supposed to be
  set in a 'policies' object rather than directly on the client options. This
  explains why reconnections were still so slow.

- Call connect() on the client before building the DB object. This provides an
  early failure detection.

eevans/restbase-mod-table-cassandra,gwicke/restbase-mod-table-cassandra