[#312] pool: Ignore ECInfoErr errors in GetSplitInfo

* Ignore `ECInfoError` errors after raw `HeadObject` request

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

pool/pool.go

@@ -3211,11 +3211,12 @@ func (p *Pool) GetSplitInfo(ctx context.Context, cnrID cid.ID, objID oid.ID, tok
 	_, err := p.HeadObject(ctx, prm)
 
 	var errSplit *object.SplitInfoError
+	var errECInfo *object.ECInfoError
 
 	switch {
 	case errors.As(err, &errSplit):
 		return errSplit.SplitInfo(), nil
-	case err == nil:
+	case err == nil || errors.As(err, &errECInfo):
 		return nil, relations.ErrNoSplitInfo
 	default:
 		return nil, fmt.Errorf("failed to get raw object header: %w", err)