Read Keyspace and Column Families from Cassandra during Storage Engine Startup

In the cassandra storage engine plugin simple prototype, search for a pre-defined keyspace named drizzle when the storage engine starts. If this keyspace is not present then the engine will not be loaded.

After this, collect the list of column families in this keyspace. These column families will correspond to tables in drizzle. Only table names corresponding to column families names can be created in the storage engine.

This limitation will be removed once online column families are supported in cassandra which is not very far away.