fix borrowing issue in nft_transfer_call
@@ -312,7 +312,7 @@ impl NonFungibleTokenCore for NonFungibleToken {
// Initiating receiver's call and the callback
ext_receiver::nft_on_transfer(
sender_id.clone(),
- old_owner,
+ old_owner.clone(),
token_id.clone(),
msg,
receiver_id.as_ref(),
