Update cassandra driver 2.1

Update com.datastax.cassandra:cassandra-driver-core library to support Cassandra 2.1.

The following error occurs when presto cassandra connector is used with Cassandra 2.1.

```
java.lang.IllegalArgumentException: replicate_on_write is not a column defined in this metadata
        at com.datastax.driver.core.ColumnDefinitions.getAllIdx(ColumnDefinitions.java:273) ~[na:na]
        at com.datastax.driver.core.ColumnDefinitions.getFirstIdx(ColumnDefinitions.java:279) ~[na:na]
        at com.datastax.driver.core.Row.getBool(Row.java:117) ~[na:na]
        at com.datastax.driver.core.TableMetadata$Options.<init>(TableMetadata.java:474) ~[na:na]
        at com.datastax.driver.core.TableMetadata.build(TableMetadata.java:107) ~[na:na]
        at com.datastax.driver.core.Metadata.buildTableMetadata(Metadata.java:128) ~[na:na]
        at com.datastax.driver.core.Metadata.rebuildSchema(Metadata.java:89) ~[na:na]
        at com.datastax.driver.core.ControlConnection.refreshSchema(ControlConnection.java:259) ~[na:na]
        at com.datastax.driver.core.ControlConnection.tryConnect(ControlConnection.java:214) ~[na:na]
        at com.datastax.driver.core.ControlConnection.reconnectInternal(ControlConnection.java:161) ~[na:na]
        at com.datastax.driver.core.ControlConnection.connect(ControlConnection.java:77) ~[na:na]
        at com.datastax.driver.core.Cluster$Manager.init(Cluster.java:890) ~[na:na]
        at com.datastax.driver.core.Cluster$Manager.newSession(Cluster.java:910) ~[na:na]
        at com.datastax.driver.core.Cluster$Manager.access$200(Cluster.java:806) ~[na:na]
        at com.datastax.driver.core.Cluster.connect(Cluster.java:158) ~[na:na]
        at com.facebook.presto.cassandra.CassandraSession$1.load(CassandraSession.java:95) ~[na:na]
        at com.facebook.presto.cassandra.CassandraSession$1.load(CassandraSession.java:90) ~[na:na]
        at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3524) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2317) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2280) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2195) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache.get(LocalCache.java:3934) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3938) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4821) ~[guava-16.0.1.jar:na]
        at com.facebook.presto.cassandra.CassandraSession.getSession(CassandraSession.java:115) ~[na:na]
        at com.facebook.presto.cassandra.CassandraSession.executeWithSession(CassandraSession.java:435) ~[na:na]
        at com.facebook.presto.cassandra.CassandraSession.getAllSchemas(CassandraSession.java:159) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider$6.call(CachingCassandraSchemaProvider.java:194) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider$6.call(CachingCassandraSchemaProvider.java:190) ~[na:na]
        at com.facebook.presto.cassandra.RetryDriver.run(RetryDriver.java:85) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider.loadAllSchemas(CachingCassandraSchemaProvider.java:189) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider.access$000(CachingCassandraSchemaProvider.java:53) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider$1.load(CachingCassandraSchemaProvider.java:113) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider$1.load(CachingCassandraSchemaProvider.java:108) ~[na:na]
        at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3524) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2317) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2280) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2195) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache.get(LocalCache.java:3934) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3938) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4821) ~[guava-16.0.1.jar:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider.getCacheValue(CachingCassandraSchemaProvider.java:328) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider.getCaseSensitiveSchemaName(CachingCassandraSchemaProvider.java:242) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider$7.call(CachingCassandraSchemaProvider.java:215) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider$7.call(CachingCassandraSchemaProvider.java:210) ~[na:na]
        at com.facebook.presto.cassandra.RetryDriver.run(RetryDriver.java:85) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider.loadAllTables(CachingCassandraSchemaProvider.java:208) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider.access$100(CachingCassandraSchemaProvider.java:53) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider$2.load(CachingCassandraSchemaProvider.java:126) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider$2.load(CachingCassandraSchemaProvider.java:121) ~[na:na]
        at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3524) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2317) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2280) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2195) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache.get(LocalCache.java:3934) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3938) ~[guava-16.0.1.jar:na]
        at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4821) ~[guava-16.0.1.jar:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider.getCacheValue(CachingCassandraSchemaProvider.java:328) ~[na:na]
        at com.facebook.presto.cassandra.CachingCassandraSchemaProvider.getAllTables(CachingCassandraSchemaProvider.java:202) ~[na:na]
        at com.facebook.presto.cassandra.CassandraMetadata.listTables(CassandraMetadata.java:126) ~[na:na]
        at com.facebook.presto.metadata.MetadataManager.listTables(MetadataManager.java:243) ~[presto-main-0.79.jar:0.79]
        at com.facebook.presto.connector.informationSchema.InformationSchemaPageSourceProvider.getTablesList(InformationSchemaPageSourceProvider.java:195) ~[presto-main-0.79.jar:0.79]
        at com.facebook.presto.connector.informationSchema.InformationSchemaPageSourceProvider.buildTables(InformationSchemaPageSourceProvider.java:177) ~[presto-main-0.79.jar:0.79]
```