event: boycotts emits vote event with non-zero votes

[cusma]

The Vote event currently emitted has:

approvals=arc4.UInt32(approvals),
rejections=arc4.UInt32(rejections),
nulls=arc4.UInt32(nulls),
boycotted=boycotted,

If boycotted=True then approvals, rejections, and nulls must all be 0.