Impossible to change repositoryPathPattern after adding repositories

Created by: slimsag

1. Add thousands of repositories to your Sourcegraph instance, wait for them to clone, etc.
2. Realize that since the browser extension repo name and Sourcegraph repo name must align, you actually needed to change repositoryPathPattern or else the browser extension won't work.
3. Edit the external service, set repositoryPathPattern... nothing happens! All repositories at /site-admin/repositories do not update, the new pattern is not respected!
4. At this point, your only resolution appears to be (a) write a script to delete all repositories or something then (b) add them all back again and wait for them to clone(!)