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

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