Fix 500 while renaming repo, fixes #7400

#### What does this MR do?

This PR fixes a regression when renaming a repo. Instead of relying to the dirty state, it get's the new path from update service. I

#### Why was this MR needed?

When renaming a repo, a 500 error is raised.

This PR fixes regression #7400

/cc @randx @dosire
This only happens if gitlab-shell can't rename the repo and should logged there. When catching the exeception it's return nil to log this to the UI