witness beneficiary not embedding close method

[zoedberg]

During Viareggio meeting we reported that the WitnessVout beneficiary doesn't embed the desired close method. It was said that this is a bug because a receiver should be able to decide this. Currently it's up to the sender to decide which close method to use in that case.

@dr-orlovsky I think we should fix this before 0.11 preview release

[dr-orlovsky]

Thank you for not forgetting!