queue module display duplicate entry when more than one user has voted to an article

When more than one user have submitted the vote, the moderation queue will display duplicate entry of the same article.

Step to reproduce:
1. Submit a new article to moderation queue
2. Login as another user and send in a vote
3. view the queue

Actual result:
- Two duplicated of the same article displayed - votes are viewed seperately.

Expected result:
- One entry for one article - vote should be the total score of the moderation point.