Hopefully fix multiple qtip bug

Summary:
If qtip tooltips can double up, I'm not entirely sure how this was supposed to work ever. Regardless, trying to fix this:

https://s3.amazonaws.com/uploads.hipchat.com/6574/33523/snvfcd5tutc0dri/upload.png

Reviewers: alex

Reviewed By: alex

Differential Revision: http://phabricator.khanacademy.org/D3880