Merge branch 'fix_permission_doc' into 'master'

fixed the documentation of the Guest role in permission.md

This MR fixes the documentation of the Guest role.  

closes gitlab-org/gitlab-ce#3777 

cc @dblessing @JobV 

See merge request !1952

doc/permissions/permissions.md

@@ -6,6 +6,9 @@ If a user is both in a project group and in the project itself, the highest perm
 If a user is a GitLab administrator they receive all permissions.
+On public projects the Guest role is not enforced.  
+All users will be able to create issues, leave comments, and pull or download the project code.  
+
 To add or import a user, you can follow the [project users and members
 documentation](doc/workflow/add-user/add-user.md).
@@ -15,8 +18,8 @@ documentation](doc/workflow/add-user/add-user.md).
 |---------------------------------------|---------|------------|-------------|----------|--------|
 | Create new issue                      | ✓       | ✓          | ✓           | ✓        | ✓      |
 | Leave comments                        | ✓       | ✓          | ✓           | ✓        | ✓      |
-| Pull project code                     | ✓        | ✓          | ✓           | ✓        | ✓      |
-| Download project                      | ✓        | ✓          | ✓           | ✓        | ✓      |
+| Pull project code                     |         | ✓          | ✓           | ✓        | ✓      |
+| Download project                      |         | ✓          | ✓           | ✓        | ✓      |
 | Create code snippets                  |         | ✓          | ✓           | ✓        | ✓      |
 | Manage issue tracker                  |         | ✓          | ✓           | ✓        | ✓      |
 | Manage labels                         |         | ✓          | ✓           | ✓        | ✓      |