osd: Optimized EC backfill interval has wrong versions

osd: Optimized EC backfill interval has wrong versions

Bug in the optimized EC code creating the backfill
interval on the primary. It is creating a map with
the object version for each backfilling shard. When
there are multiple backfill targets the code was
overwriting oi.version with the version
for a shard that has had partial writes which
can result in the object not being backfilled.

Can manifest as a data integirty issue, scrub
error or snapshot corruption.

Signed-off-by: Bill Scales <bill_scales@uk.ibm.com>
(cherry picked from commit acca514f9a3d0995b7329f4577f6881ba093a429)