sstable: read_toc: always close file
sstable: read_toc: always close file

Use utils::with_file helper to always close the file
new_sstable_component_file opens.

Signed-off-by: Benny Halevy <23c997c90eb8537635e9392d48e7af1bf1b2ca22@scylladb.com>

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