*Note* This PR doesn't add any feature or change any behavior. Feel free to close the PR if not required.
While I was working on course visibility settings, I followed the documentation but couldn't achieve the desired behavior. No matter what setting I set in course advanced settings, course was always visible in the catalog. After searching on net for some time, I came to know (from a google group I guess) that I have to change the permission values.
Therefore I had to change the permission values in my `private.py` file.
This PR changes the values of `COURSE_CATALOG_VISIBILITY_PERMISSION` and
`COURSE_ABOUT_VISIBILITY_PERMISSION` to the permissions that will
actually depict the desired behaviors. I think it makes more sense that I don't have to change the settings to achieve the behavior described in the documentation.
It's just my personal opinion. Feel free to close the PR if its unnecessary.