[#1024] blobovnicza: Copy data on iterate

DB value is only valid while the tx is alive.
But handler may to run something in other goroutine.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/blobovnicza/iterate.go

@@ -1,6 +1,7 @@
 package blobovnicza
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"math"
@@ -159,7 +160,7 @@ func (b *Blobovnicza) Iterate(ctx context.Context, prm IteratePrm) (IterateRes,
 				}
 
 				if !prm.withoutData {
-					elem.data = v
+					elem.data = bytes.Clone(v)
 				}
 
 				return prm.handler(elem)