#4770 should check if svn checkout url is valid [ss311]
[forge:site-support:#311]
Even if we can't guess what the proper checkout URL should be, we should at least be able to check to see if it's valid.
If "trunk" doesn't exist in a migrated/imported repo, we should drop that. And when setting a new checkout URL, it should give an error message if the dir doesn't exist.
Dupe of [#3027]
Related
Tickets:
#3027