Show "new merge request" buttons in canonical repo when one has a fork
Dev: https://dev.gitlab.org/gitlab/gitlabhq/issues/2380
As discussed in gitlab-com/www-gitlab-com#337 (closed)
When you are on the original repo there should always be a new merge request button:
- If you have at least developer access it should create an MR at the repo
- If you have a fork it should go to the new MR screen there
- If you don't have a fork yet it should fork