Redmine

When POST'ing to repositories#fetch_changesets, we fetch changesets and then just render the show page This retains the URL of the fetch_changesets action in the browser bar, e.g.

https://redmine.example.com/projects/test/repository/demo/fetch_changesets

Furthermore, the rendered page is the result of a POST and is thus not easily reloaded. Thus, I propose that instead of directly showing the repository again, we issue a redirect to the repository's show page. That way, the fetch_changesets URL is not visible ion the browser's address bar and the page can be easily reloaded.

This is implemented in the attached patch.