sstables: Fix off-by-one when checking for max_data_segregation_window_count
sstables: Fix off-by-one when checking for max_data_segregation_window_count

Make sure max size of known windows will respect max_d_s_w_c.

Signed-off-by: Raphael S. Carvalho <1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@scylladb.com>
Message-Id: <20200305165014.16022-1-1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@scylladb.com>

scylladb/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla