Consider changing default keyspace name

[tommystendahl]

To make migrations when you want to run the old ecchronos in parallell with ecchronos-agent during the migration a little more straight forward maybe we should change the default name of the ecchronos keyspace. We could use the name "ecchronos_agent" to be in line with everything else.

[VictorCavichioli]

The schema from repair_history, lock, lock_priority, on_demand_repair_status haven't being changed, we have just included nodes_sync table, so I believe that both old and new ecchronos can share the these tables (it need to be tested), as the design of these tables already consider distributed information and repairs executed by different ecchronos instances

[tommystendahl]

Since the old ecchronos and the agent can share keyspace and tables I will close this since no actions are needed.