pkg/storage/segments: Clarify logic in Repair method (#2621)

Create a new variable rather than reusing the existing one because the
name of the existing one is confusing when reading the logic and it
requires more time that the logic doesn't have a bug.

pkg/storage/segments/repairer.go

@@ -216,16 +216,17 @@ func (repairer *Repairer) Repair(ctx context.Context, path storj.Path) (err erro
 	mon.FloatVal("healthy_ratio_after_repair").Observe(healthyRatioAfterRepair)
 
 	// if partial repair, include "unhealthy" pieces that are not duplicates
+	revisedPointerPieces := healthyPieces
 	if healthyLength < pointer.Remote.Redundancy.SuccessThreshold {
 		for _, p := range unhealthyPieces {
 			if _, ok := healthyMap[p.GetPieceNum()]; !ok {
-				healthyPieces = append(healthyPieces, p)
+				revisedPointerPieces = append(revisedPointerPieces, p)
 			}
 		}
 	}
 
 	// Update the remote pieces in the pointer
-	pointer.GetRemote().RemotePieces = healthyPieces
+	pointer.GetRemote().RemotePieces = revisedPointerPieces
 
 	// Update the segment pointer in the metainfo
 	return repairer.metainfo.Put(ctx, path, pointer)