Merge branch 'fc/remote-testgit-feature-done'

In the longer term, tightening rules is a good thing to do, and because nobody who has worked in the remote helper area seems to be interested in reviewing this, I would assume they do not think such a retroactive tightening will affect their remote helpers. So let's advance this topic to see what happens. * fc/remote-testgit-feature-done: remote-testgit: properly check for errors