test: lib: reusable_sst: save unexpected errors
test: lib: reusable_sst: save unexpected errors

reusable_sst tries openeing an sstable using
all sstable format versions in descending order.

It is expected to see "file not found" if the
actual sstable version is not the latest one.

That said, we may hit other error if the sstable
is malformed in any way, so do not override
this kind of error if "file not found" errors
are hit after it, and return the unexpected error
instead.

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

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