Challenge discussions are accessible to the user even after unregister from the challenge

Steps Log in as TopConnCustomer and check the bookmarks (should have a discussion book marked from an existing forum) Unregister from the challenge and check the book marks again

Actual result Book marks list still show the unregistered challenge's bookmarked discussion and the user can continue creating new discussions and adding comment etc on the same challenge forum

Bookmark after unregister.zip

Final Submission Guidelines

Git issue link: https://github.com/topcoder-platform/forums/issues/178