R1:2dc8065d1143

Prevent Repository local path edit from the web UI

Summary:
Ref T4039. This fixes an issue where a user with the ability to create repositories could view repositories he is otherwise not permitted to see, by following these steps:

- Suppose you want to see repository "A".
- Create a repository with the same VCS, called "B".
- Edit the local path, changing "/var/repo/B" to "/var/repo/A".
- Now it points at a working copy of a repository you can't see.
- Although you won't be able to make it…