When one of the categories listed on the Message Boards Home tab is already subscribed to, the context menu for that category still has the option to "Subscribe" rather than "Unsubscribe."
This is due to the fact that category_action.jsp is using an old method of getting the list of subscribed categories, so there appear to be none.
Steps to reproduce:
1. Add a Message Boards portlet to a page
2. Add a category to the Message Boards
3. Click the category's context menu (the 3 vertical dots)
4. Click "Subscribe"
5. When the request completes, click the category's context menu again
Expected result: option has changed to "Unsubscribe"
Actual result: the menu still only has the option to "Subscribe"