Ability to readd bounty (delete and add again)

[churik]

User Story

As a user, I want to delete label "bounty" when I have problem with deploying contract, ethereum network congestion or if I changed my mind or added bounty by mistake.

Description

Type: Feature Summary: when bounty has 0.00 value, or contract address is freezing in deployment stage, I want to remove bounty label and expect that bounty will disappear from SOB. If I add bounty label again, new bounty should again appear on SOB. I suggest to add this feature for contract which don't have money yet, in order to avoid such situations like in issue #184

Expected behavior

I delete bounty label > bounty disappears from SOB site I add bounty label again > bounty appears on SOB site and I can send money and use it like form scratch

Actual behavior

I delete bounty label > bounty does not disappear from SOB site

It can be one of the stage #174

I guess it will be right, if after removing bounty old contract is removed as well, and new one is generated when you add bounty label again