Normally, once a bounty is placed, it cannot be removed, under any circumstances. Well, that's not true; Moderators will sometimes remove bounties that were strategically placed only to keep a question from being closed, when said question should be closed. (that situation obviously does not apply to your bounty)
I'm giving you the benefit of the doubt, and I have done something you should never expect to happen again: I have refunded/removed the bounty on the question you linked. Another user flagged it and pointed to this discussion, and I am inclined to chalk that up to a language-confusion issue.
The main reason I am doing this is because you came here almost instantly upon realizing your mistake - not after a few days of gaining the benefit of a bounty (increased attention for the question), and because I think you may have misunderstood how it all works.
But don't do that again, because you won't get another bounty refunded. :)