Watches don't respect filter contraints

You can add constraints to your view using the filter which will be respected by the watch.

Unfortunately, there seems to be a bug in the way this is being applied at the moment. The constraint doesn't exist at the user profile watches.

Steps to reproduce:

1. Go to 'Source' tab and click on a repository
2. Select a directory and click on 'Activity' tab
3. Click on 'Filter' check box an set the constraint (e.g committer see filter.png)
4. Click "Apply Constraints" button
5. Select "watch" at the "Tools" drop down
6. Check the watches via the user profile (see watches.png)