'nodetool enable/disablebackup' callback was modifying only the
existing keyspaces and column families configurations.
However new keyspaces/column families were using
the original 'incremental_backups' configuration value which could
be different from the value configured by 'nodetool enable/disablebackup'
user command.
This patch updates the database::_enable_incremental_backups per-shard
value in addition to updating the existing keyspaces and column families
configurations.
Fixes#845
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
2cd836a02e